Publications

  • Yangui, A., Bescond, M., Yan, T. et al. Evaporative electron cooling in asymmetric double barrier semiconductor heterostructures. Nat Commun 10, 4504 (2019) doi:10.1038/s41467-019-12488-9
  • Zhang Y, Qiu B, Nagai N, et al. Enhanced thermal sensitivity of MEMS bolometers integrated with nanometer-scale hole array structures[J]. AIP Advances, 2019, 9(8): 085102.
  • Zhang Y, Hosono S, Nagai N, et al. Fast and sensitive bolometric terahertz detection at room temperature through thermomechanical transduction[J]. Journal of Applied Physics, 2019, 125(15): 151602.
  • S. Du, K. Yoshida, Y. Zhang, I. Hamada, and K. Hirakawa: “Terahertz dynamics of electron-vibron coupling in single moleculeswith tunable electrostatic potential”, Nature Photonics 12, 608-612(2018), doi:10.1038/s41566-018-0241-1 .
  • A. Ishida, K. Naruse, S. Nakashima, Y. Takano, S. Du, and K. Hirakawa: “Interband absorption in PbTe/PbSnTe-based type-II superlattices”, Applied Physics Letters, vol. 113, issue 7, pp. 072103-1~4 (2018) Aug., DOI: 10.1063/1.5042764.
  • Q. Weng, K. Lin, K. Yoshida, H. Nema, S. Komiyama, S. Kim, K. Hirakawa, and Y. Kajihara: “Near-field radiative nano-thermal imaging of non-uniform Joule heating in narrow metal wires”, Nano Letters, vol. 18, no. 7, pp. 4220-4225, (2018) Jun., DOI: 10.1021/acs.nanolett.8b01178.
  • M. Jung, K. Yoshida., K. Park, X.-X. Zhang, C. Yesilyurt, Z. B. Siu, M. B. A. Jalil, J.W. Park, J. Park, N. Nagaosa, J. Seo, and K. Hirakawa: “Quantum Dots Formed in Three-dimensional Dirac Semimetal Cd3As2 Nanowires”, Nano Letters, vol. 18, no. 3, pp. 1863–1868 (2018) Feb. DOI: 10.1021/acs.nanolett.7b05165.
  • M. Bescond, D. Logoteta, F. Michelini, N. Cavassilas, T. Yan, A. Yangui, M. Lannoo, and K. Hirakawa: “Thermionic cooling devices based on resonant-tunneling AlGaAs/GaAs heterostructure”, Journal of Physics: Condensed Matter, vol. 30, no. 6, pp.064005-1~8 (2018) Feb., DOI: 10.1088/1361-648X/aaa4cf.
  • S. Du, K. Yoshida, Y. Zhang, I. Hamada, and K. Hirakawa: “Terahertz dynamics of electron-vibron coupling in single moleculeswith tunable electrostatic potential”, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), arXiv:1712.07339 [cond-mat.mes-hall] (Submitted on 20 Dec 2017).
  • Y. Otsuka, R. Shirakashi, and K. Hirakawa: “Bound states of water in gelatin discriminated by near-infrared spectroscopy”, Japanese Journal of Applied Physics, vol.56, pp. 111602-1~6 (2017) Oct., DOI: 10.7567/JJAP.56.111602.
  • K. Shibata, K. Yoshida, K. Daiguji, H. Sato, T. Ii, and K. Hirakawa: “Electric-field control of conductance in metal quantum point contacts by electric-double-layer”, Applied Physics Letters, vol. 111, pp. 153104-1~4, (2017) Oct., DOI: 10.1063/1.4995318.
  • Y. Zhang, S. Hosono, N. Nagai,and K. Hirakawa: ” Effect of buckling on the thermal response of microelectromechanical beam resonators”. Appl. Phys. Lett. 111, 023504 (2017)Jul., DOI: 10.1063/1.4993740.
  • K. Yoshida, and K. Hirakawa: “Stochastic resonance in bistable atomic switches”, Nanotechnology, vol. 28, no. 12, pp. 125205-1~5 (2017) Feb., DOI: 10.1088/1361-6528/aa5ee1.
  • A. Naka, K. Hirakawa, and T. Unuma: “Capacitive response and room-temperature terahertz gain of a Wannier–Stark ladder system in GaAs-based superlattices”, Applied Physics Express, vol. 9, no. 11, pp. 112101-1~4 (2016) Oct., DOI: 10.7567/APEX.9.112101.
  • Y. Zhang, Y. Watanabe, S. Hosono, N. Nagai, and K. Hirakawa:“Room temperature, very sensitive thermometer using a doubly clamped microelectromechanical beam resonator for bolometer applications”.Appl. Phys. Lett. 108, 163503 (2016).
  • Y. Zhang, K. Shibata, N. Nagai, C. Ndebeka-Bandou, G. Bastard, and K. Hirakawa: “Excited-state charging energies in quantum dots investigated by terahertz photocurrent spectroscopy”, Phys. Rev. B 93, (2016) 235313.
  • K. Yoshida, K. Shibata, and K. Hirakawa: “Terahertz Field Enhancement and Photon-Assisted Tunneling in Single-Molecule Transistors”, Phys. Rev. Lett. 115, (2015) 138302
  • Y. Zhang, K. Shibata, N. Nagai, C. Ndebeka-Bandou, G. Bastard, and K. Hirakawa: “Gate-controlled terahertz single electron photovoltaic effect in self-assembled InAs quantum dots”, Appl. Phys. Lett. 107, (2015) 103103
  • Y. Zhang, K. Shibata, N. Nagai, C. Ndebeka-Bandou, G. Bastard, and K. Hirakawa: “Probing many-body quantum states in single InAs quantum dots: Terahertz and tunneling spectroscopy”, Phys. Rev. B 91, (2015) 241301(R)
  • Y. Zhang, K. Shibata, N. Nagai, C. Ndebeka-Bandou, G. Bastard, and K. Hirakawa: “Terahertz intersublevel transitions in single self-assembled InAs quantum dots with variable electron numbers”, Nano Letters 15, (2015) 1166-1170
  • N. Okamura, K. Yoshida, S. Sakata ,and K. Hirakawa: “Electron transport in endohedral metallofullerene Ce@C82 single-molecule transistors”, Appl. Phys. Lett. 106, (2015) 043108
  • K Shibata, N. Pascher, P. J. J. Luukko, E. Rasanen, S. Schnez, T. Ihn, K. Ensslin, and K. Hirakawa: “Electron magneto-tunneling through single self-assembled InAs quantum dashes”, Applied Physics Express, vol. 7, pp. 045001-1~4, (2014) Mar., .DOI: 10.7567/APEX.7.045001.
  • K. Shibata and K. Hirakawa, “Terahertz photon-assisted tunneling in InAs quantum dots”, Journal of Infrared, Millimeter, and Terahertz Waves, vol. 35, issue 1, pp. 101-109, (2014) Jan., DOI:10.1007/s10762-013-0039-7 (invited)
  • S. Sakata, K. Yoshida, Y. Kitagawa, K. Ishii, and K. Hirakawa: “Rotation and anisotropic molecular orbital effect in a single H2TPP molecule transistor”, Physical Review Letters, vol. 111, issue 24, pp. 246806-1~5, (2013), Dec.12, DOI:10.1103/PhysRevLett.111.246806.
  • K. Shibata, H. Yuan, Y. Iwasa, and K. Hirakawa: “Large modulation of zero-dimensional electronic states in quantum dots by electric-double-layer gating”, Nature Communications 4, Article number: 2664, pp.1-7, (2013) Oct., DOI:10.1038/ncomms3664.
  • W. Shimizu, N. Nagai, K. Kohno, K. Hirakawa, and M. Nomura: “Waveguide coupled air-slot photonic crystal nanocavity for optomechanics”, Optics Express, vol. 21, no. 19, pp. 21961-21969, (2013) Sep. DOI:10.1364/OE.21.021961
  • H. Li, K. Hirakawa, and J. C. Cao: “How important is the influence of poisson potential on the band structures of terahertz quantum-cascade lasers?”, Japanese Journal of Applied Physics, vol.52, pp. 082701-1~5, (2013) Jul., DOI: 10.7567/JJAP.52.082701.
  • S. Takahashi, RS. Deacon, A. Oiwa, K. Shibata, K. Hirakawa, S. Tarucha: “Electrically tunable three-dimensional g-factor anisotropy in single InAs self-assembled quantum dots”, Physical Review B, vol. 87, issue 16, pp. 161302-1~5, (2013) Apr., DOI: 10.1103/PhysRevB.87.161302.
  • K. Yoshida, I. Hamada, S. Sakata, A. Umeno, M. Tsukada, and K. Hirakawa: “Gate-tunable large negative tunnel magnetoresistance in Ni–C60–Ni single molecule transistors”, Nano Letters, vol. 13, issue 2, pp. 481-485, (2013), Feb., DOI: 10.1021/nl303871x.
  • 平川一彦: “量子ナノ構造とテラヘルツ電磁波”、Optics plus Electronics, vol. 35, no. 2, pp. 137-142 (2013) Jan.25.
  • K. M. Cha, K. Shibata, and K. Hirakawa: “Single electron transport through site-controlled InAs quantum dots”, Applied Physics Letters, vol. 101, pp. 223115-1~5, (2012) Nov., DOI: 10.1063/1.4769039
  • T. Ihara, J. R. Cardenas, Y. Sakasegawa, R. Ferreira, G. Bastard, and K. Hirakawa: “Quenching of the transient miniband photoconductivity in semiconductor superlattices due to a cancellation of field acceleration by Bragg reflection”, Physical Review B, vol. 86, pp. 161305-1~5, (2012). Oct. DOI: 10.1103/PhysRevB.86.161305
  • K. Shibata, A. Umeno, K. M. Cha, and K. Hirakawa: “Photon-assisted tunneling through self-assembled InAs quantum dots in the terahertz frequency range”, Physical Review Letters, vol.109, no. 7, pp. 077401-1~4, (2012). Aug., DOI:10.1103/PhysRevLett.109.077401.
  • Z. Wang, K. Ishibashi, S. Komiyama, N. Nagai, and K. Hirakawa: “Integrating a plasmonic coupler to photo detector of terahertz frequency”, Applied Physics Letters, vol. 101, pp. 091114-1~3,(2012).Aug., DOI: 10.1063/1.4748581.
  • K. M. Cha, I. Horiuchi, K. Shibata, and K. Hirakawa: “Size-limiting effect of site-controlled InAs Qquantum dots grown at high temperatures by molecular beam epitaxy”, Applied Physics Express 5, pp. 085501-1 ~3, (2012) . Jul., DOI:10.1143/APEX.5.085501.
  • 平川一彦、柴田憲治、梅野顕憲: “ナノギャップ電極を用いた量子トランジスタの作製と電子伝導”、Journal of the Vacuum Society of Japan vol. 55、 no. 7、pp. 321-327、(2012). Jul. (招待解説論文)
  • Y. Kanai, R. S. Deacon, A. Oiwa, K. Yoshida, K. Shibata, K. Hirakawa, and S. Tarucha: “Control of supercurrent in a self-assembled InAs quantum dot Josephson junction by electrical tuning of level overlaps”, Applied Physics Letters 100, pp.202109-1~3 (2012). May, DOI:10.1063/1.4719072.
  • H. Yasuda, T. Kubis, I. Hosako, and K. Hirakawa: “Non-equilibrium Green’s function calculation for GaN-based terahertz-quantum cascade laser structures”, Journal of Applied Physics, vol. 111, issue 8, pp. 083105-1~4 (2012). Apl. DOI: 10.1063/1.4704389.
  • K. M. Cha, K. Shibata, M. Kamiko, R. Yamamoto, and K. Hirakawa: “Chemical composition and thermal stability of atomic force microscope-assisted anodic oxides as nanomasks for molecular beam epitaxy”, Japanese Journal of Applied Physics 50, pp.120205-1~3, (2011) . Nov.
  • K. Shibata, K. Seki, P. J. J. Luukko, E. Räsänen, K. M. Cha, I. Horiuchi, and K. Hirakawa: “Electronic structures in single self-assembled InAs quantum dashes detected by nanogap metal electrodes”, Applied Physics Letters, vol. 99, issue 18, pp. 182104-1-3, (2011), Nov. , DOI:10.1063/1.3659479.
  • Y. Kanai, R. S. Deacon, S. Takahashi, A. Oiwa, K. Yoshida, K. Shibata, K. Hirakawa, Y. Tokura and S. Tarucha: “Electrically tuned spin–orbit interaction in an InAs self-assembled quantum dot”, Nature Nanotechnology, vol. 6, pp.511-516, (2011) Aug.
  • 平川一彦、梅野顕憲、吉田健治、坂田修一: “金属ナノ接合におけるエレクトロマイグレーションの素過程と単一分子トランジスタ作製への応用”、表面科学、vol. 32, no.10, pp. 635-640、(2011). Oct. (招待論文).
  • R. S. Deacon, Y. Kanai, S. Takahashi, A. Oiwa, K. Yoshida, K. Shibata, K. Hirakawa, Y. Tokura, and S. Tarucha: “Electrically tuned g tensor in an InAs self-assembled quantum dot”, Physical Review B, vol 84, pp. 041302-1~5, (2011).Jul.
  • T. Unuma, Y. Ino, K.-E. Peiponen, E. M. Vartiainen, M. Kuwata-Gonokami, and K. Hirakawa: “Causality-based method for determining the time origin in terahertz emission spectroscopy”, OPTICS EXPRESS, vol. 19, pp. 12759-12765 (2011). Jun.
  • 梅野顕憲、吉田健治、坂田修一、平川一彦: “原子スケールの金属ナノ接合におけるエレクトロマイグレーションの素過程”, 固体物理, vol. 46, No. 4, pp. 21-31 (2011). Apr..
  • T. Unuma, S. Takata, Y. Sakasegawa, K. Hirakawa, and A. Nakamura: “Intersubband transition energy and linewidth modified by a submonolayer AlAs insertion into GaAs quantum wells”, Journal of Applied Physics, vol. 109, pp.043506-1~4, (2011). Feb.
  • K. Shibata, K. Seki, K. M. Cha, I. Horiuchi1, and K. Hirakawa: “Growth of self-assembled InAs quantum dashes and their applications to single electron transistors”, AIP conference proceeding series, vol. 1399 , pp. 273-274 (2011).
  • T. Ihara, K. Hirakawa, R. Cardenas, R. Ferreira, and G. Bastard: ”Excitonic and continuum contributions to terahertz emission from semiconductor superlattices”, AIP conference proceeding series, vol. 1399 , pp. 427-428 (2011).
  • K. M. Cha, K. Shibata, I. Horiuchi, M. Kamiko, R. Yamamoto, and K. Hirakawa: ” Chemical composition and thermal stability of AFM anodic oxides as nanomasks for site-controlled InAs QDs “, AIP conference proceeding series, vol. 1399 , pp. 239-240 (2011).
  • M. Grochol, T. Ihara, R. Ferreira, K. Hirakawa and G. Bastard: “Boltzmann approach beyond the relaxation time approximation for transient Bloch emission from semiconductor superlattices”, AIP conference proceeding series, vol. 1399, pp. 359-360 (2011).
  • S. Kim, R. Ishiguro, M. Kamio, Y. Doda, E. Watanabe, D. Tsuya, K.Shibata, K. Hirakawa and H. Takayanagi: ”Side-gate controlled electrical properties of superconducting quantum interference device coupled with self-assembled InAs quantum dot”, AIP conference proceeding series AIP conference proceeding series, vol. 1399 , pp. 383-384 (2011).
  • Y. Kanai, R. S. Deacon, S. Takahashi, A. Oiwa, K. Yoshida, K. Shibata, Y. Tokura, K. Hirakawa and S. Tarucha: “Spin-orbit interaction detection using Kondo effect in single self-assembled InAs quantum dots”, AIP conference proceeding series, vol. 1399 , pp. 355-356 (2011).
  • K. H. Park, S. Takagi and K. Hirakawa: “Remote impurity scattering in Si MOSFETs with thin gate oxides –possible screening effect by mobile charges in the gate electrodes -”, AIP conference proceeding series, vol. 1399 , pp. 353-354 (2011).
  • S. Kim, R. Ishiguro, M. Kamio, Y. Doda, E. Watanabe, D. Tsuya, K. Shibata , K. Hirakawa, and H. Takayanagi: “π junction transition in InAs self-assembled quantum dot coupled with SQUID” , Applied Physics Letters, vol. 98, pp. 063106-1~3, (2011). Feb.
  • S. Sakata, A. Umeno, K. Yoshida, and K. Hirakawa, “Critical voltage for atom migration in ballistic copper nanojunctions and its implications to interconnect technology for very large scaleintegrated circuits”, Applied Physics Express (APEX), vol. 3, issue no. 11, pp.115201-1~3, (2010). Nov.
  • A. Umeno and K. Hirakawa, “Spectroscopic analysis of electromigration at gold nanojunctions”, Physica E: Low-dimensional systems and nanostructures, vol. 42, pp. 2826-2829 (2010). Oct.
  • K. Shibata, M. Jung, K. M. Cha, and K. Hirakawa, “Control of tunnel coupling strength between InAs quantum dots and nanogap metallic electrodes through In-Ga intermixing”, Physica E, vol. 42, pp.2595-2597 (2010). Sept.
  • Y. Kanai, R. S. Deacon, A. Oiwa, K. Yoshida, K. Shibata, K. Hirakawa, and S. Tarucha, “Electrical control of Kondo effect and superconducting transport in a side-gated InAs quantum dot Josephson junction”, Physical Review B, vol. 82, pp.054512-1~8, (2010). Aug
  • Y. Sakasegawa, T. Ihara, and K. Hirakawa, “Terahertz photonic band gap for the transverse-magnetic modes formed by using a planar waveguide structure with a photonic crystal electrode “, Applied Physics Letters, vol. 97, pp.051110-1~3, (2010). Aug.
  • J. R. Cardenas, T. Ihara, R. Ferreira, K. Hirakawa, and G. Bastard, “Excitation spectra of terahertz Bloch emission in semiconductor superlattices “, Physical Review B, vol. 82, pp. 041310-1~4, (2010). Jul.
  • T. Unuma, Y. Ino, M. K.-Gonokami, E. M. Vartiainen, K.-E. Peiponen, and K. Hirakawa, “Determination of the time origin by the maximum entropy method in time-domain terahertz emission spectroscopy “, OPTICS EXPRESS, vol.18, No.15, pp. 15853-15858, (2010). Jul
  • S. Takahashi, R. S. Deacon, K. Yoshida, A. Oiwa, K. Shibata, K. Hirakawa, Y. Tokura, and S. Tarucha, “Large Anisotropy of the Spin-Orbit Interaction in a Single InAs Self-Assembled Quantum Dot “, Physical Review Letters, vol.104, pp.246801-1~4 (2010). June
  • 平川一彦, “半導体ブロッホ発振器:実現に向けた課題と展望”, 応用物理, vol. 79、No. 3、pp.235-238 (2010). 3月
  • R. S. Deacon, Y. Tanaka, A. Oiwa, R. Sakano, K. Yoshida, K. Shibata, K. Hirakawa, and S. Tarucha, “Kondo-enhanced Andreev transport in single self-assembled InAs quantum dots contacted with normal and superconducting leads”, Physical Review B, No.81, pp. 121308(R) (2010). Mar
  • K. Yoshida, A. Umeno, S. Sakata, and K. Hirakawa, “Structural Stability of Ni Quantum Point Contacts under Electrical Stresses”, Applied Physics Express, vol. 3, pp.045001-1~3 (2010). Mar
  • R. Moriya, H. Kobayashi, K. Shibata, S. Masubuchi, K. Hirakawa, S. Ishida, Y. Arakawa, and T. Machida, “Fabrication of single-electron transistor composed of a self-assembled quantum dot and nanogap electrode by atomic force microscope local oxidation”, Applied Physics Express, vol. 3, p. 035001-1~3 (2010). Mar
  • T. Unuma, Y. Ino, M. Kuwata-Gonokami, G. Bastard, and K. Hirakawa, “Transient Bloch oscillation with the symmetry-governed phase in semiconductor superlattices”, Physical Review B No. 81, pp. 125329-1~6 (2010). Mar.
  • K. Shibata, M. Jung, K. M. Cha, and K. Hirakawa, “Control of tunnel coupling strength between InAs quantum dots and nanogap metallic electrodes through In-Ga intermixing”, Physica E, vol. 42, (2010). Feb
  • A. Umeno and K. Hirakawa, “Spectroscopic Analysis of Electromigration at Gold Nanojunctions”, Physica E, vol. 42, (2010). Feb
  • K. Ikushima, D. Asaoka, S. Komiyama, T. Ueda, K. Hirakawa, “Manipulating terahertz photons on a quantum Hall effect device”, Physica E, vol. 42, pp. 1034-1037(2010). Feb
  • R. S. Deacon, Y. Tanaka, A. Oiwa, R. Sakano, K. Yoshida, K. Shibata, K. Hirakawa, and S. Tarucha, “Tunneling Spectroscopy of Andreev Energy Levels in a Quantum Dot Coupled to a Superconductor”, Physical Review Letters, No. 104, pp.076805 (2010). Feb
  • K. Yoshida, A. Umeno, S. Sakata, and K. Hirakawa, “Importance of Moisture Control in Formation of Nanogap Electrodes by Electrical Break Junction Method”, Japanese Journal of Applied Physics, Rapid communication, vol. 48, pp.120216-120218 (2009). Dec.
  • A. Umeno and K. Hirakawa, “Spectroscopic Analysis of Electromigration at Gold Nanojunctions”, Physica E, Kobe International Conference Center, Kobe, Japan (2009). Jul
  • K. Shibata, M. Jung, K. M. Cha, M. Sotome, and K. Hirakawa, “Control of tunnel coupling strength between InAs quantum dots and nanogap metallic electrodes through In-Ga intermixing”, Physica E, Kobe International Conference Center, Kobe, Japan (2009). Jul
  • R. S. Deacon, Y. Kanai, A. Oiwa, K. Yoshida, K. Shibata, K. Hirakawa, and S. Tarucha, “Proximity supercurrent in self assembled InAs quantum dots”, AIP Conference Proceedings Series, (2009)
  • K. Hamaya, M. Kitabatake, K. Shibata, M. Jung, S. Ishida, T. Taniyama, K. Hirakawa, Y. Arakawa, and T. Machida, “Spin-related current suppression in a semiconductor quantum dot spin-diode structure”, Physical Review Letters, vol.102, Issue 23, pp.236806~236809 (2009). Jun
  • R. Ferreira, T. Unuma, K. Hirakawa, G. Bastard, “A Boltzmann approach to transient Bloch emission from semiconductor superlattices”, Applied Physics Express (APEX), vol. 2, Issue number. 6, article number. 062101 (2009). Jun
  • A. Umeno and K. Hirakawa, “Non-thermal origin of electromigration at gold nanojunctions in the ballistic regime”, Applied Physics Letters, vol. 94, pp.162103-1~3 (2009). Apl
  • K. Shibata, M. Jung, K. M. Cha, M. Sotome, and K. Hirakawa, “Effect of In-Ga intermixing on the electronic states in self-assembled InAs quantum dots probed by nanogap electrodes “, Applied Physics Letters. Vol. 94, pp.162107-1~3 (2009). Apl
  • H. Yasuda, T. Kubis, P. Vogl, N. Sekine, I. Hosako, and K. Hirakawa, “Non-equilibrium Green’s function calculation for four-level scheme terahertz quantum cascade lasers”, Applied Physical Letters, vol. 94, pp. 151109-1~3 (2009). Apl
  • T. Ueda, S. Komiyama, Z. An, N. Nagai, and K. Hirakawa, “Temperature dependence of the performance of charge-sensitive infrared phototransistors”, Journal of Applied Physics, vol. 105, pp.064517-1~064517-8 (2009). Mar
  • K. Shibata, K. Hirakawa, “The Kondo effect observed up to TK~80 K in self-assembled InAs quantum dots laterally coupled to nanogap electrodes”, Journal of Crystal Growth, vol. 311, Issue. 7, pp.1795-1798 (2009). Mar
  • S.Masubuchi, M.Ono, K.Yoshida, K.Hirakawa, and T.Machida, “Fabrication of graphene nanoribbon by local anodic oxidation lithography using atomic force microscope”, Applied Physics Letter, vol.94, Issue 8, pp. 082107~082109 (2009). Feb
  • M. Jung, W. Song, J-S. Lee, N. Kim, J. Kim, J. Park, H. Lee and K. Hirakawa, “Electrical breakdown and nanogap formation of indium oxide core/shell heterostructure nanowires”, Nanotechnology, vol. 19, p.495702 (2008).
  • Y. M. Zhu, T. Unuma, K. Shibata, K. Hirakawa, Y. Ino, and M. Kuwata-Gonokami, “Power dissipation spectra and terahertz intervalley transfer gain in bulk GaAs under high electric fields”, Applied Physics Letters, vol. 93, pp. 232102-1~3 (2008).
  • Y. M. Zhu, T. Unuma, K. Shibata, and K. Hirakawa, “Femtosecond acceleration of electrons under high electric fields in bulk GaAs investigated by time-domain terahertz spectroscopy”, Applied Physics Letters, vol. 93, pp.042116-1~3 (2008).
  • K. Shibata, and K. Hirakawa, “High Kondo temperature (TK~80 K) in self-assembled InAs quantum dots laterally coupled to nanogap electrodes”, Applied Physics Letters, vol. 93, pp. 062101-1~3 (2008).
  • Y. M. Zhu, T. Unuma, K. Shibata, K. Hirakawa, Y. Ino, and M. Kuwata-Gonokami, “Femtosecond very high-field transport in bulk GaAs investigated by time-domain terahertz spectroscopy”, Physica Status Solidi (c), 5, No.1, pp. 240-243 (2008).
  • K. Shibata, C. Buizert, A. Oiwa, K. Hirakawa, and S. Tarucha, “Electron transport through single self-assembled InAs quantum dots coupled to superconducting nanogap electrodes”, Physica Status Solidi (c), 5, No.1, pp.178-181 (2008).
  • K. Hamaya, M. Kitabatake, K. Shibata, M. Jung, M. Kawamura, S. Ishida, T. Taniyama, K. Hirakawa, Y. Arakawa, and T. Machida, “Oscillatory changes in the tunneling magnetoresistance effect in semiconductor quantum-dot spin valves”, Physical Review B, vol. 77, pp. 081302-1~4(2008).
  • K. Hamaya, M. Kitabatake, K. Shibata, M. Jung, M. Kawamura, K. Hirakawa, T. Machida, T. Taniyama, S. Ishida, and Y. Arakawa, “Kondo effect in a semiconductor quantum dot coupled to ferromagnetic electrodes”, Applied Physics Letters, vol. 91, pp. 232105 (2007).
  • C. Buizert, A. Oiwa, K. Shibata, K. Hirakawa, and S. Tarucha, “Kondo universal scaling for a quantum dot coupled to superconducting leads”, Physical Review Letters, vol.99, pp.136806 (2007).
  • T. Kondo and K. Hirakawa, “Terahertz radiation from ultrahigh-speed field-effect transistors induced by ultrafast optical gate switching”, Applied Physics Letters, vol. 91, pp.191120-1~3 (2007).
  • K. Ikushima, H. Sakuma, S. Komiyama, and K. Hirakawa, “Visualization of quantum Hall edge channels through imaging of terahertz emission”, Physical Review B, vol.76, pp.165323-1~6 (2007).
  • Z. An, T. Ueda, S. Komiyama, and K. Hirakawa, “Metastable excited states of a closed quantum dot with high sensitivity to infrared photons”, Physical Review B, vol.75, pp.085417-1~7 (2007).
  • T. Akasaka, A. Umeno, S.-H. Hong, K. Hirakawa, and K. Araki, “Novel gold nanoparticles/conjugated molecules network structures fabricated by self-assembling process”, AIP Conf. Proc., vol.893, p.361 (2007).
  • A. Umeno, T. Akasaka, S.-H. Hong, and K. Hirakawa, “Atomistic picture of electromigration process and its application to high-yield fabrication of nanogap electrodes”, AIP Conf. Proc., vol.893, p.373 (2007).
  • T. Unuma, K. Kobayashi, A. Yamamoto, M. Yoshita, K. Hirakawa, Y. Hashimoto, S. Katsumoto, Y. Iye, Y. Kanemitsu, and H. Akiyama, “Single-particle nature of intersubband electronic Raman scattering and dynamical many-body effects in narrow GaAs quantum wells”, AIP Conf. Proc., vol.893, p.475 (2007).
  • T. Unuma, N. Sekine, and K. Hirakawa, “Dephasing of Bloch oscillations due to Interface roughness scattering in GaAs/AlAs superlattices”, AIP Conf. Proc., vol.893, pp.495 (2007).
  • K.-H. Park, K. Hirakawa, and S. Takagi, “Low-temperature mobilities and energy loss rates of two-dimensional electrons in Si inversion layers”, AIP Conf. Proc., vol.893, pp.601 (2007).
  • K. Hirakawa, T. Unuma, and N. Sekine, “Dispersive terahertz Bloch gain in semiconductor superlattices”, AIP Conf. Proc., vol.922, pp.191 (2007).
  • Y. Igarashi, M. Jung, M. Yamamoto, A. Oiwa, T. Machida, K. Hirakawa, and S. Tarucha, “Spin-half Kondo effect in a single self-assembled InAs quantum dot with and without an applied magnetic field”, Physical Review B, vol. 76, pp.081303-1~4 (2007).
  • K. Shibata, C. Buizert, A. Oiwa, K. Hirakawa, and S. Tarucha, “Lateral electron tunneling through single self-assembled InAs quantum dots coupled to superconducting nanogap electrodes”, Applied Physics Letters, vol. 91, No. 11, pp. 112102-1~3 (2007).
  • K. Hamaya, M. Kitabatake, K. Shibata, M. Jung, M. Kawamura, K. Hirakawa, and T. Machida, “Electric-field control of tunneling magnetoresistance effect in a Ni/InAs/Ni quantum-dot spin valve”, Applied Physics Letters, vol. 91, No. 2, 022107-1~3 (2007).
  • K. -H. Park, T. Unuma, K. Hirakawa, and S. Takagi, “Determination of deformation potential constant of the conduction band in Si from electron heating experiments on Si metal-oxide-semiconductor field-effect transistors”, Applied Physics Letters, vol. 91, No. 13, pp. 132118-1~8 (2007).
  • M. Gel, T. Ishida, T. Akasaka, A. Umeno, K. Araki, K. Hirakawa, and H. Fujita, “Mechanically controlled quantum contact with on-chip MEMS Actuator”, Journal of Microelectromechanical Systems, vol. 16, No. 1, pp.1~6 (2007).
  • K. Shibata, M. Jung, K. Hirakawa, T. Machida, and H. Sakaki, S. Ishida and Y. Arakawa, “Electronic properties of self-assembled InAs quantum dots on GaAs surfaces probed by lateral electron tunneling structures”, Journal of Crystal Growth, vol. 301-302, pp. 731-734. (2007).
  • S.W. Lee, T.G. Kim, K. Hirakawa, J.S. Kim, S.H. Choi, and H.Y. Cho, “Lateral photoconductivity and bound states of self-assembled Ge/Si quantum dots”, Nanotechnology, vol.18, No. 10, P. 105403 (2007).
  • K. Hamaya, S. Masubuchi, M. Kawamura, T. Machida, M. Jung, K. Shibata, K. Hirakawa, T. Taniyama, S. Ishida, and Y. Arakawa, “Spin transport through a single self-assembled InAs quantum dot with ferromagnetic leads”, Applied Physics Letters, vol. 90, No. 5, pp. 053108-1~3 (2007).
  • T. Unuma, N. Sekine, and K. Hirakawa, “Dephasing of Bloch oscillating electrons in GaAs-based superlattices due to interface roughness scattering”, Applied Physics Letters, vol. 89, No. 16, pp. 161913-1~3 (2006).
  • Yu.A. Tarakanov, M. A. Odnoblyudov, K. A. Chao, N. Sekine, and K. Hirakawa, “Scattering-assisted terahertz gain in semiconductor superlattices”, Physical Review B, vol. 74, No. 12, pp. 125321-1~8 (2006).
  • P. Han, K.-J. Jin, Y.-L. Zhou, Q.-L. Zhou, and K. Hirakawa, “Terahertz radiation in superlattices in moderate electric field”, International Journal of Modern Physics B, vol. 20, No. 8, pp. 937-945 (2006).
  • M. Jung, K. Hirakawa, S. Ishida, Y. Arakawa, and S. Komiyama, “Electron transport and shell structures of single InAs quantum dots probed by nanogap electrodes”, Physica E Vol. 32, Issues 1-2, May, pp. 187-190 (2006).
  • K. Hirakawa and N. Sekine, “Carrier dynamics and dispersive terahertz Bloch gain in semiconductor superlattices (invited)”, Physica E, Vol. 32, Issues 1-2, May, pp. 320-324 (2006).
  • K. Ikushima, H. Sakuma, Y. Yoshimura, S. Komiyama, T. Ueda, and K. Hirakawa, “THz imaging of cyclotron emission in quantum Hall conductors”, Physica E , vol. 34, pp. 22-26 (2006).
  • 平川一彦、関根徳彦、島田洋蔵, ”半導体超格子のブロッホ振動:非古典的振動子のテラヘルツ利得”, 「応用物理」, No. 6, (2006).
  • K. Hamaya, S. Masubuchi, K. Hirakawa, S. Ishida, Y. Arakawa, K. Sawano, Y. Shiraki, and T. Machida, “Spin-dependent edge-channel transport in a Si/SiGe quantum Hall system”, Physical Review B, vol. 73, p. 121304-1~4 (2006).
  • K. Ikushima, Y. Yoshimura, T. Hasegawa, S. Komiyama, T. Ueda, and K. Hirakawa, “Photon-counting microscopy of terahertz radiation”, Applied Physics Letters, vol. 88, No. 15, pp. 152110-1~3 (2006).
  • S. Komiyama, H. Sakuma, K. Ikushima, and K. Hirakawa, “Electron temperature of hot spots in quantum Hall conductors”, Physical Review B, vol. 73, p. 045333-1~5 (2006).
  • T. Unuma, K. Kobayashi, A. Yamamoto, M. Yoshita, K. Hirakawa, Y. Hashimoto, S. Katsumoto, Y. Iye, Y. Kanemitsu, and H. Akiyama, “Collective and single-particle intersubband excitations in narrow quantum wells selected by infrared absorption and resonant Raman scattering”, Physical Review B, vol. 74, No. 19, pp.195306-1~5 (2006).
  • S.-W. Lee and K. Hirakawa, “Lateral conduction quantum dot infrared photodetectors using photoionization of holes in InAs quantum dots”, Nanotechnology, vol. 17, No. 15, pp. 3866-3868 (2006).
  • Z. An, T. Ueda, J.-C. Chen, S. Komiyama, and K. Hirakawa, “A sensitive double quantum well infrared phototransistor”, Journal of Applied Physics, vol. 100, p. 044509 (2006).
  • J.-C. Chen, Z. An, T. Ueda, S. Komiyama, K. Hirakawa, and V. Antonov, “Metastable excited states of a closed quantum dot probed by an aluminum single-electron transistor”, Physical Review B, vol. 74, p. 045321 (2006).
  • H. Sakuma, K. Ikushima, S. Komiyama, and K. Hirakawa, “Spectral measurement of weak THz waves with quantum Hall detectors”, Infrared Physics and Technology, vol. 48, No. 3, pp. 235-239, (2006).
  • Z. An, J.-C. Chen, T. Ueda, S. Komiyama, and K. Hirakawa, “Infrared phototransistor using capacitively coupled two-dimentional electron gas layers”, Applied Physics Letters, vol. 86, No. 17, pp. 172106-1~3 (2005).
  • N. Sekine, Y. Shimada, and K. Hirakawa, “Ultrafast carrier dynamics in semiconductor superlattices: terahertz gain and dephasing mechanism (invited paper)”, Proc. SPIE Int. Soc. Opt. Eng., vol. 5725, p. 352 (2005).
  • S.-W. Lee, C. J. Park, T. W. Kang, H. Y. Cho, and K. Hirakawa, “Photoconductivity in lateral conduction self-assembled Ge/Si quantum dot infrared photodetectors “, Proc. SPIE Int. Soc. Opt. Eng., vol. 5726, p. 146 (2005).
  • Yu. A. Tarakanov, V. Vettchinkina, M. A. Odnoblyudov, K. A. Chao, N. Sekine, and K. Hirakawa, “Scattering-assisted electric current in semiconductor superlattices in the Wannier-Stark regime”, Physical Review B, vol. 72, No. 125345 (2005).
  • M. Jung, N. Sekine, K. Hirakawa, S. Ishida, Y. Arakawa, Y. Kawaguchi, and S. Komiyama, “Single electron transistors using single self-assembled InAs quantum dots”, Inst. Phys. Conf. Ser., No. 184, Section 1, pp. 31-34 (2005).
  • 平川一彦、関根徳彦, ”テラヘルツ電磁波で見る半導体中の電子波束の超高速ダイナミクス”, 光学, vol. 34, No. 9, pp. 458-464 (2005).
  • M. Jung, T. Machida, K. Hirakawa, S. Komiyama, T. Nakaoka, S. Ishida, and Y. Arakawa, “Shell structures in self-assembled InAs quantum dots probed by lateral electron tunneling structures”, Applied Physics Letters, vol. 87, No. 20, pp. 203109-1~3 (2005).
  • M. Jung, K. Hirakawa, S. Ishida, Y. Arakawa, Y. Kawaguchi, and S. Komiyama, “Shell structures in self-assembled InAs quantum dots observed by lateral single electron tunneling structures”, AIP Conference Proceeding, vol. 772, p. 635 (2005).
  • K. Ikushima, H. Sakuma, S. Komiyama, and K. Hirakawa, “Imaging non-equilibrium edge states in quantum Hall conductors”, AIP Conference Proceeding, vol. 772, p. 569 (2005).
  • N. Sekine and K. Hirakawa, “Acceleration dynamics of Bloch oscillating electrons in semiconductor superlattices investigated by terahertz electro-optic sampling method”, AIP Conference Proceeding, vol. 772, p. 1224 (2005).
  • A. Umeno and K. Hirakawa, “Fabrication of atomic-scale gold junctions by electrochemical plating technique using a common medical disinfectant”, AIP Conference Proceeding, vol. 772, p. 1071 (2005).
  • A. Vojvodic, A. Blom, Z. Ma, Y. Shimada, K. Hirakawa, and K. A. Chao, “Zener tunneling between Wannier Stark levels in GaAs/AlGaAs superlattices”, Solid State Communication, vol. 136, pp. 580-584 (2005).
  • A. Umeno and K. Hirakawa, “Fabrication of atomic-scale gold junctions by electrochemical plating using a common medical liquid”, Applied Physics Letters, vol. 84, No. 14, pp. 143103-1~3 (2005).
  • N. Sekine and K. Hirakawa, “Dispersive terahertz gain of non-classical oscillator: Bloch oscillation in semiconductor superlattices”, Physical Review Letters, vol. 94, No. 5, 057408 (2005).
  • M. Jung, K. Hirakawa, Y. Kawaguchi, S. Komiyama, S. Ishida, and Y. Arakawa, “Lateral electron transport through single self-assembled InAs quantum dots”, Applied Physics Letters, vol. 86, No. 3, 033106 (2005).
  • K. Ikushima, H. Sakuma, S. Komiyama, and K. Hirakawa, “Imaging of cyclotron emission from edge channels in quantum Hall conductors”, Physical Review Letters, vol. 93, No. 14, pp. 146804-1~4 (2004).
  • N. Sekine, Y. Shimada, and K. Hirakawa, “Bloch gain in AlGaAs/GaAs semiconductor superlattices”, Physica E, vol. 21, pp. 858 – 862 (2004).
  • Y. Shimada, N. Sekine, and K. Hirakawa, “Inter-miniband resonant Zener tunneling in wide-miniband GaAs/Al0.3Ga0.7As superlattices investigated by THz Emission spectroscopy”, Physica E, pp. 661 – 665 (2004).
  • M. Jung and K. Hirakawa, “Lateral electron transport through single InAs quantum dots”, Physica E, vol. 21, pp. 423 – 425 (2004).
  • 関根徳彦、島田洋蔵、平川一彦, ”半導体超格子のブロッホゲイン”, 固体物理, vol. 39, No. 2, pp. 25-36 (2004).
  • Y. Shimada, N. Sekine, and K. Hirakawa, “THz emission due to inter-miniband resonant Zener tunneling in wide-miniband GaAs/Al0.3Ga0.7As superlattices”, Applied Physics Letters, vol. 84, No. 24, pp. 4926-4928 (2004).
  • K. Jin, M. Odnoblyudov, Y. Shimada, K. Hirakawa, and K. A. Chao, “Terahertz frequency radiation from Bloch oscillations in GaAs/Al0.3Ga0.7As superlattices”, Physical Review B, vol. 68, No. 15, pp. 153315-153318 (2003).
  • K. Hirakawa, Y. Shimada, M. Odnoblioudov, and K. A. Chao, “Dynamical carrier transport and terahertz gain in semiconductor superlattices”, Proc. SPIE Int. Soc. Opt. Eng., vol. 4992, p.138 (2003).
  • N. Sekine, Y. Shimada, and K. Hirakawa, “Dephasing mechanisms of Bloch oscillations in GaAs/Al0.3Ga0.7As superlattices investigated by time-resolved terahertz spectroscopy”, Applied Physics Letters, vol. 83, No. 23, pp. 4794-4796 (2003).
  • Y. Shimada, K. Hirakawa, M. Odnoblioudov, and K. A. Chao, “Terahertz conductivity and possible Bloch gain in semiconductor superlattices”, Physical Review Letters, vol. 90, No. 4, pp. 46806-46809 (2003).
  • Y. Shimada and K. Hirakawa, “Time-resolved THz spectroscopy of miniband transport in biased GaAs/AlGaAs superlattices”, Inst. Phys. Conf. Ser. No. 170: Chapter 6, pp. 395-400 (2002).
  • Y. Shimada, K. Hirakawa, and S.-W. Lee, “Time-resolved terahertz emission spectroscopy of wide miniband GaAs/AlGaAs superlattices”, Applied Physics Letters vol. 81, No. 9, pp. 1642-1644 (2002).
  • M. Abe, S. Madhavi, Y. Shimada, Y. Otsuka, K. Hirakawa, and K. Tomizawa, “Transient carrier velocities in bulk GaAs: quantitative comparison between terahertz data and emsemble Monte Carlo calculations”, Applied Physics Letters, vol. 81, No. 4, pp. 679-681 (2002).
  • S. Madhavi, M. Abe, Y. Shimada, and K. Hirakawa, “Non-equilibrium electron transport in wide miniband GaAs/AlGaAs superlattices at room temperature”, Physical Review B, vol. 65, pp. 193308-193311 (2002).
  • K. Hirakawa, S. Katsumoto, T. Hayashi, Y. Hashimoto, and Y. Iye, “Double-exchange-like interaction in Ga1-xMnxAs investigated by infrared absorption spectroscopy”, Physical Review B, vol. 65, pp. 193312-193315 (2002).
  • Y. Kawaguchi, K. Hirakawa, and S. Komiyama, “High-sensitivity quantum Hall far-infrared photodetector integrated with log-periodic antenna”, Applied Physics Letters, vol. 80, No. 18, pp. 3418-3420 (2002).
  • K. Hirakawa, S.-W. Lee, Ph. Lelong, S. Fujimoto, K. Hirotani, and H. Sakaki, “High-sensitivity modulation-doped quantum dot infrared photodetectors (invited)”, Microelectronic Engineering vol. 63, pp. 185-192 (2002).
  • O. Astafiev, S. Komiyama, T. Kutswa, V. Antonov, Y. Kawaguchi, and K. Hirakawa, “A single-photon detector in the microwave range”, Applied Physics Letters, vol. 80, pp. 4250-4252 (2002).
  • S. -W. Lee and K. Hirakawa, “Lifetime of photoexcited carriers in modulation-doped quantum dot infrared photodetectors”, Physica E, vol. 13, pp. 305-308 (2002).
  • Y. Kawaguchi, K. Hirakawa, M. Saeki, K. Yamanaka, and S. Komiyama, “Performance of high-sensitivity quantum Hall far infrared photodetectors”, Applied Physics Letters, vol. 80, No. 1, pp. 136-138 (2002).
  • K. Hoshino, T. Someya, K. Hirakawa, and Y. Arakawa, “Observation of intersubband transition from the first to the third subband (e1-e3) in GaN/AlGaN quantum wells”, Physica Status Solidi A-Applied Research, vol. 192, No. 1, pp. 27-32 (2002).
  • K. Hoshino, T. Someya, K. Hirakawa, and Y. Arakawa, “Low-pressure MOCVD growth of GaN/AlGaN multiple quantum wells for intersubband transitions”, Jouranl of Crystal Growth, vol. 237, pp. 1163-1166 (2002).
  • N. Sekine, K. Hirakawa, M. Vossebuerger, P. Haring Bolivar, and H. Kurz, “Crossover from coherent to incoherent excitation of two-dimensional plasmons in GaAs/AlGaAs single quantum wells by femtosecond laser pulses”, Physical Review B (Rapid Communication), vol. 64, pp. 201323(R) (2001).
  • K. Hirakawa, K. Yamanaka, M. Endo, and S. Komiyama, “Far-infrared photoresponse of the magnetoresistance of the two-dimensional electron systems in the integer quantized Hall regime”, Physical Review B, vol. 63, pp. 85320-85324 (2001).
  • Ph. Lelong, K. Hirakawa, K. Hirotani, S.-W. Lee, and H. Sakaki, “Fano profiles in bound-to-continuum intersubband transitions in negatively charged InAs quantum dots”, Proceedings of the 25th International Conference on the Physics of Semiconductors, ed. by N. Miura and T. Ando, Springer, pp. 1163-1164 (2001).
  • K. Hoshino, T. Someya, K. Hirakawa, and Y. Arakawa, “Observation of intersubband transition in AlGaN/GaN single heterostructures”, Proc. 25th Int. Conf. Phys. Semicond. (Eds. N. Miura and T. Ando), pp. 1527-1528 (2001).
  • Y. Shimada, T. Matsuno, and K. Hirakawa, “THz emission due to miniband transport in GaAs/AlGaAs superlattices”, Japanese Journal of Applied Physics, vol. 40, Part 1, No. 4B, pp. 3009-3011 (2001).
  • K. Hirakawa, A. Oiwa, and H. Munekata, “Infrared optical conductivity of In1-xMnxAs”, Physica E, vol. 10, pp. 215-218 (2001).
  • S. Katsumoto, T. Hayashi, Y. Hashimoto, Y. Iye, Y. Ishiwata, M. Watanabe, R. Eguchi, T. Takeuchi, Y. Harada, S. Shin, and K. Hirakawa, “Magnetism and metal-insulator transition in III-V based diluted magnetic semiconductors”, Journal of Materials Science and Engineering B, vol. B84, pp. 88-95 (2001).
  • Y. Kawano, S. Komiyama, and K. Hirakawa, “Suppression of electron-hole pair recombination in edge states in quantum Hall regimes”, Physica B, vol. 298, No. 1-4, pp. 33-37 (2001).
  • S. Katsumoto, T. Hayashi, Y. Hashimoto, Y. Iye, Y. Ishiwata, M. Watanabe, R. Eguchi, T. Takeuchi, Y. Harada, S. Shin and K. Hirakawa, “Nature of magnetism in III-V based diluted magnetic semicondutors”, IPAP Conference Series 2 Proceedings of the 10th International Conference on Narrow Gap Semiconductors and Related Small Energy Phenomena, Physics and Applications -NGS10-, pp. 261-264 (2001).
  • Ph. Lelong, S.-W. Lee, K. Hirakawa, and H. Sakaki, “Fano profile in intersubband transitions in InAs quantum dots”, Physica E, vol. 7, pp. 174-178 (2000).
  • S.-W. Lee, K. Hirakawa, and Y. Shimada, “Modulation-doped quantum dot infrared photodetectors using self-assembled InAs quantum dots”, Physica E, vol. 7, pp. 499-502 (2000).
  • S. -W. Lee, K. Hirakawa, and Y. Shimada, “Mid-infrared photodetector using self-assembled InAs quantum dots embedded in modulation doped GaAs quantum wells”, MRS Symposia Proceedings, Vol. 607 Infrared Applications of Semiconductors III, pp. 147-152 (2000).
  • N. Sekine, K. Yamanaka, K. Hirakawa, M. Vosseburger, P. Haring-Bolivar, and H. Kurz: “Observation of terahertz radiation from higher-order two-dimensional plasmon modes in GaAs/AlGaAs single quantum wells”, Applied Physics Letters, vol. 74, No. 7, pp. 1006-1008 (1999).
  • S.-W. Lee, K. Hirakawa, and Y. Shimada: “Bound-to-continuum intersubband photoconductivity of self-assembled InAs quantum dots in modulation-doped heterostructures”, Applied Physics Letters, vol. 75, No. 10, pp. 1428-1430 (1999).
  • N. Sekine, K. Hirakawa, M. Vosseburger, P. Haring-Bolivar, and H. Kurz: “Excitation process of two-dimensional plasmons excited by femtosecond laser pulses”, Microelectronic Engineering, vol. 47, pp. 289-292 (1999).
  • N. Sekine, K. Hirakawa, M. Vosseburger, P. Haring-Bolivar, and H. Kurz: “Coherent and incoherent excitation of two-dimensional plasmons in AlGaAs/Gas quantum wells by femtosecond laser pulses”, Inst. Phys. Conf. Ser., No. 162, pp. 845-848 (1999).
  • 平川一彦、川口 康、山中宏治、小宮山進: ”量子ホール効果を用いた超高感度遠赤外光検出”、応用物理、 vol. 68、 No. 9、 pp. 1027-1033 (1999).
  • K. Tamura, K. Hirakawa, and Y. Shimada: “Drude absorption and electron localization in GaAs/AlGaAs superlattices”, Physica B, vol. 272, pp. 183-186 (1999).
  • K. Yamanaka and K. Hirakawa: “Far infrared photoresponse of the diagonal magnetoresistance of the two-dimensional electron system near the n=1 spin-gap quantum hall state”, Physica Status Solidi (B), vol.204, pp. 310-313 (1998).
  • R. A. Hogg, K. Suzuki, K. Tachibana, L. Finger, K. Hirakawa, and Y. Arakawa: “Optical spectroscopy of self-assembled type II GaSb/GaAs quantum dot structures grown by molecular beam epitaxy”, Applied Physics Letters, vol. 72, No. 22, pp. 2856-2858 (1998).
  • N. Sekine, K. Hirakawa, and Y. Arakawa: “Terahertz emission from quantum beats in coupled quantum wells”, Japanese Journal of Applied Physics, vol. 37, part. 1, No. 3B, pp. 1643-1645 (1998).
  • Y. Shimada, and K. Hirakawa: “Optical and transport properties of single quantum well infrared photodetectors”, Japanese Journal of Applied Physics, vol. 37, part 1, No. 3B, pp. 1421-1423 (1998).
  • K. Yamanaka and K. Hirakawa: “Far-infrared photoresponse of the AlGaAs/GaAs low-dimensional systems constricted by split-gates”, Solid-State Electronics, vol. 42, No. 7-8, pp. 1151-1153 (1998).
  • Y. Shimada and K. Hirakawa: “Photocurrent dynamics in single quantum well infrared photodetectors investigated by using free electron laser pulses”, Nuclear Instruments and Methods in Physics Research, B 144, pp. 166-171 (1998).
  • H. Sakakibara and K. Hirakawa: “Interaction effects on cyclotron resonance in semiconductor double quantum well structures”, Physica B, vol. 249-251, pp. 855-858 (1998).
  • Y. Shimada and K. Hirakawa: “Time constant for high-field domain formation in multiple quantum well sequential resonant tunneling diodes”, Japanese Journal of Applied Physics, vol. 36, part 1, No. 3B, pp. 1944-1947 (1997).
  • Y. Shimada, and K. Hirakawa: “Sequential resonant magnetotunneling through landau levels in GaAs/AlGaAs multiple quantum well structures”, Physica Status Solidi (B), vol. 204, pp. 427-430 (1997).
  • K. Hirakawa, I. Wilke, K. Yamanaka, H. G. Roskos, M. Vosseburger, F. Wolter, C. Waschke, H. Kurz, M. Grayson, and D. C. Tsui: “Coherent submillimeter-wave emission from non-equilibrium two-dimensional free carrier plasmas in AlGaAs/GaAs heterojunctions”, Surface Science, vol. 361/362, pp. 368-371 (1996).
  • M. Vosseburger, H. G. Roskos, F. Wolter, C. Wacshke, H. Kurz, K. Hirakawa, I. Wilke, and K. Yamanaka: “Radiative decay of optically excited coherent plasmons in a two-dimensional electron gas”, Journal of the Optical Society of America B, vol. 13, No. 5, pp. 1045-1053 (1996).
  • K. Hirakawa, Y. Shimada, and T. Ikoma: “Supply-function dependent sequential resonant tunneling in semiconductor multiple quantum well diodes”, Physica B, vol. 227, pp. 202-205 (1996).
  • Y. Shimada, K. Hirakawa: “Condition for the high-field domain formation in semiconductor multiple quantum well sequential resonant tunneling structures”, Japanese Journal of Applied Physics, vol. 36, part 1, No. 3A, pp.1012-1014 (1996).
  • 平川一彦、 山中宏治、M. A. Grayson、D. C. Tsui: ”半導体ナノ構造中のホットな低次元電子系からの遠赤外放射”、固体物理、 vol. 31、 No. 4、 pp.277 – 286 (1996).
  • N. Sekine, K. Hirakawa, F. Sogawa, Y. Arakawa, N. Usami, Y. Shiraki, and T. Katoda: “Ultrashort lifetime photocarriers in Ge thin films”, Applied Physics Letters, vol. 68, No. 24, pp.3419-3421 (1996).
  • S.-N. Wang, K. Yamanaka, K. Hirakawa, M. Noguchi and T. Ikoma: “Direct determination of bare confinement potentials in AlGaAs/GaAs split-gate single quantum wires by far infrared spectroscopy”, Japanese Journal of Applied Physics (Part 2), vol.35, No.10A, pp. L1249-L1252 (1996).
  • T. Ikoma, T. Hiramoto, and K. Hirakawa: “Gap between microelectronics and nanoelectronics”, Inst. Phys. Conf. Ser., vol. 145, pp. 23-28 (1996).
  • 関根徳彦、 十川文博、平川一彦、荒川泰彦: ”集積化光伝導ダイポールアンテナによるテラヘルツ光の発生と検出”、電子情報通信学会論文誌 C-I、 vol. J79-C-I、 No. 11、 pp. 446-447 (1996).
  • K. Hirakawa, M. Endo, K. Yamanaka, Y. Hisanaga, and S. Komiyama: “Giant negative far-infrared response of the diagonal magnetoresistance due to edge channel transport in the quantized Hall regime”, Proceedings of the 23rd International Conference on the Physics of Semiconductors, vol. 3, pp. 2543-2546 (1996).
  • M. Grayson, D. C. Tsui, M. Shayegan, K. Hirakawa, R. A. Ghanbari, and H. I. Smith: “Far infrared emission from hot quasi-one dimensional quantum wires in GaAs”, Applied Physics Letters, vol. 67, No. 11, pp. 1564 – 1566 (1995).
  • S. Suzuki, L. E. Henrickson, K. Hirakawa, and T. Ikoma: “Coherent transport through electron wave directional coupling structures”, Japanese Journal of Applied Physics part 1, vol. 34, No. 8B, pp. 4449 – 4451 (1995).
  • K. Hirakawa, K. Yamanaka, M. Grayson, and D. C. Tsui: “Far infrared emission spectroscopy of hot two-dimensional plasmons in Al0.3Ga0.7As/GaAs heterojunctions”, Applied Physics Letters, vol. 67, No. 16, pp. 2326 – 2328 (1995).
  • N. Sakamoto, K. Hirakawa, and T. Ikoma: “Conduction-type conversion in Si-doped (311)A GaAs grown by molecular beam epitaxy”, Applied Physics Letters, vol. 67, No.10, pp. 1444 – 1446 (1995).
  • J. J. Heremans, M. B. Santos, K. Hirakawa, and M. Shayegan: “Mobility anisotropy of two-dimensional hole systems in (311)A GaAs/AlxGa1-xAs heterojunctions”, Journal of Applied Physics, vol. 76, No. 3, pp. 1980-1982 (1994).
  • K. Hata, T. Ikoma, K. Hirakawa, T. Okano, A. Kawazu, T. Ueda, and M. Akiyama: “Spontaneous appearance of high index facets during the evolution of step bunching on vicinal GaAs (001)”, Journal of Applied Physics, vol. 76, p. 5601 (1994).
  • K. Agawa, K. Hirakawa, N. Sakamoto, Y. Hashimoto, and T. Ikoma: “Electrical properties of heavily Si-doped (311)A GaAs grown by molecular beam epitaxy”, Applied Physics Letters, vol. 65, No. 9, pp. 1171-1173 (1994).
  • K. Agawa, Y. Hashimoto, K. Hirakawa, N. Sakamoto, and T. Ikoma: “Heavy p- and n-type doping with Si on (311)A GaAs substrates by molecular beam epitaxy”, IEICE Transactions on Electronics, vol. E77-C, No. 9, pp. 1408-1413 (1994).
  • N. Sakamoto, K. Hirakawa, and T. Ikoma: “Conduction-type conversion in Si-doped (311)A GaAs grown by molecular beam epitaxy”, Applied Physics Letters, vol. 67, No. 10, pp. 1444-1446 (1994).
  • K. Hirakawa, M. Grayson, D. C. Tsui, and C. Kurdak: “Blackbody radiation from hot two-dimensional electrons in AlxGa1-xAs/GaAs heterojunctions”, Physical Review B, vol. 47, No. 24, pp. 16651-16654 (1993).
  • K. Hirakawa, Y. Zhao, M. B. Santos, M. Shayegan, and D. C. Tsui: “Anomalous cyclotron-resonance line splitting of two-dimensional holes in (311)A AlxGa1-xAs/GaAs heterojunctions”, Physical Review B, vol. 47, No. 7, pp. 4076-4079 (1993).
  • T. S. Lay, J. J. Heremans. Y. W. Suen, M. B. Santos, K. Hirakawa, and M. Shayegan: “High-quality two-dimensional electron system confined in an AlAs quantum well”, Applied Physics Letters, vol. 62, No. 24, pp. 3120-3122 (1993).
  • Y. Hashimoto, T. Saito, K. Hirakawa, and T. Ikoma: “Role of ultrathin Si layers inserted at GaAs/AlAs heterointerfaces”, Gallium Arsenide and Related Compounds 1992, Inst. Phys. Conf. Series, vol. 129, No. 259-264 (1993).
  • K. Hirakawa, Y. Zhao, M. B. Santos, M. Shayegan, and D. C. Tsui: “Anomalous cyclotron resonance line splitting of two-dimensional holes in (311)A AlGaAs/GaAs heterojunctions”, Proceedings of 21st International Conference on the Physics of Semiconductors, pp. 911-914 (1993).
  • Y. Zhao, D. C. Tsui, K. Hirakawa, M. Santos, M. Shayegan, R. A. Ghanbari, D. A. Antoniadis, and H. I. Smith: “Far infrared magneto-absorption by the 2DEG in GaAs/AlGaAs heterostructures with grid gates”, Proceedings of 21st International Conference on the Physics of Semiconductors, pp. 903-906 (1993).
  • Y. Hashimoto, G. Tanaka, K. Hirakawa, and T. Ikoma: “Role of ultrathin Si layer in GaAs/AlAs heterostructure”, Proceedings of 21st International Conference on the Physics of Semiconductors, pp. 725-728 (1993).
  • S. Y. Lin, K. Hirakawa, A. Zaslavsky, D. C. Tsui, and J. Klem: “Subband dispersion of holes in AlAs/In0.1Ga0.90As/AlAs strained-layer quantum wells measured by resonant magnetotunneling”, Applied Physics Letters, vol. 60, No. 5, pp.601-603 (1992).
  • L.E. Henrickson, K. Hirakawa, J. Frey, and T. Ikoma: “Application of the tight-binding green’s function method to interface roughness in resonant tunneling heterostructures”, Journal of Applied Physics, vol. 71, No. 8, pp. 3883-3888 (1992).
  • M. Yamada, K. Hirakawa, T. Odagiri, T. J. Thornton, and T. Ikoma: “Electron scatterers near the boundary in AlGaAs/GaAs quantum wires fabricated by focused ion beam implantation”, Superlattice and Microstructures, vol. 11, No. 3, pp. 261-264 (1992).
  • K. Hirakawa, Y. Hashimoto, and T. Ikoma: “Transient of microscopic valence charge distribution and electrostatic potential at GaAs/AlAs heterointerfaces”, Surface Science, vol. 267, pp. 166-170 (1992).
  • M. Noguchi, K. Hirakawa, and T. Ikoma: “In-situ determination of electronic properties of clean GaAs (100) surfaces by high resolution electron energy loss spectroscopy”, Surface Science, vol. 271, pp. 260-276 (1992).
  • G. Tanaka, K. Hirakawa, H. Ichinose, and T. Ikoma: “Atomically flat AlGaAs/GaAs(110) heterointerface grown by molecular beam epitaxy”, Gallium Arsenide and Related Compounds 1991, Inst. Phys. Conf. Series, No. 120, pp. 25-30 (1992).
  • T. Odagiri, K. Hirakawa, and T. Ikoma: “Electron scattering in AlGaAs/GaAs hetero-quantum wires”, Quantum Effect Physics, Electronics and Applications, Inst. Phys. Conf. Series, No. 127, pp. 157-162 (1992).
  • M. Noguchi, K. Hirakawa, and T. Ikoma: “Conductance oscillation in a quantum point contact of high-mobility hole gas”, Quantum Effect Physics, Electronics and Applications, Inst. Phys. Conf. Series, No. 127, pp. 179-182 (1992).
  • M. Noguchi, K. Hirakawa, and T. Ikoma: “Intrinsic electron accumulation layers on reconstructed clean InAs (100) surfaces”, Physical Review Letters, vol. 66, No. 17, pp. 2243-2246 (1991).
  • K. Hirakawa, Y. Hashimoto, K. Harada, and T. Ikoma: “Strain effect on band offsets at pseudomorphic InAs/GaAs heterointerfaces characterized by x-ray photoemission spectroscopy”, Physical Review B, vol. 44, No. 4, pp. 1734-1740 (1991).
  • K. Hirakawa, Y. Hashimoto, K. Harada, and T. Ikoma: “Strain induced change in band offsets at pseudomorphically grown InAs/GaAs heterointerfaces characterized by X-ray photoelectron spectroscopy”, Journal of Crystal Growth, vol. 111, pp. 393-396 (1991).
  • K. Hirakawa, Y. Hashimoto, and T. Ikoma: “Transient of electrostatic potential at GaAs/AlAs heterointerfaces characterized by x-ray photoemission spectroscopy (invited)”, Proceedings of SPIE, vol. 1361, pp. 255-261 (1991).
  • K. Hirakawa, H. Sakaki, and T. Ikoma: “Electron-phonon interaction in GaAs/AlxGa1-xAs/GaAs single-barrier heterojunction diodes”, Surface Science, vol. 229, pp. 161-164 (1990).
  • K Hirakawa, Y. Hashimoto, and T. Ikoma: “Orientation independence of heterojunction-band offsets at GaAs-AlAs heterointerfaces characterized by x-ray photoemission spectroscopy”, Applied Physics Letters, vol. 57, No. 24, pp. 2555-2557 (1990).
  • K. Hirakawa, Y. Hashimoto, T. Saito, and T. Ikoma: “Direct experimental estimation of interface dipole effect of GaAs/AlAs heterojunction band offset by x-ray photoelectron spectroscopy”, Gallium Arsenide and Related Compounds ’89, Inst. Phys. Conf. Ser., IOP Publishing Ltd., vol. 106, pp. 345-350 (1990).
  • X. -W. Zhao, K. Hirakawa, and T. Ikoma: “Diffusion and photoluminescence of erbium in GaAs and InP”, Gallium Arsenide and Related Compounds ’89, Inst. Phys. Conf. Ser., IOP Publishing Ltd., vol. 106, pp. 277-282 (1990).
  • K. Hirakawa: “Tunneling spectroscopy of GaAs/AlxGa1-xAs/GaAs single-barrier heterojunction diodes”, Physical Review B, vol. 40, No. 5, pp. 3451-3454 (1989).
  • T. Hiramoto, K. Hirakawa, T. Ikoma, and Y. Iye: “Anomalous drain conductance in quasi-one-dimensional AlGaAs/GaAs quantum wires”, Nanostructure Physics and Fabrication, Academic Press, pp. 176-182 (1989).
  • T. Hiramoto, K. Hirakawa, Y. Iye, and T. Ikoma: “Phase coherence length of electron waves in narrow AlGaAs/GaAs quantum wires fabricated by focused ion beam implantation”, Applied Physics Letters, vol. 54, No. 21, pp. 2103-2105 (1989).
  • X. -W. Zhao, K. Hirakawa, and T. Ikoma: “Intracenter transition in triply ionized erbium ions diffused into III-V compound semiconductors”, Applied Physics Letters, vol. 54, No 8, pp. 712-714 (1989).
  • J. Wakabayashi, A. Fukano, S. Kawaji, K. Hirakawa, H. Sakaki, Y. Koike, and T. Fukase: “Fractional quantum Hall Effect at n=1/7”, Journal of the Physical Society of Japan (1989).
  • T. Hiramoto, T. Odagiri, K. Hirakawa, Y. Iye, and T. Ikoma: “Anomalous drain conductance in quasi-one-dimensional AlGaAs/GaAs quantum wire transisitors fabricated by focused ion beam implantation”, Proceedings of the 1st International workshop on Nanostructure Physics and Fabrication (1989).
  • T. Hiramoto, K. Hirakawa, and T. Ikoma: “Fabrication of one-dimensinal GaAs wires by focused ion beam implantation”, Journal of Vacuum Science and Technology, vol. B6, No. 3, pp. 1014-1017 (1988).
  • T. Hiramoto, K. Hirakawa, and T. Ikoma: “Quasi-one-dimensional planar GaAs wires fabricated by focused ion beam implantation”, Inst. Phys. Conf. Ser., No. 91: Chapter 5, pp. 431-434 (1988).
  • K. Hirakawa, T. Noda, and H. Sakaki: “Interface roughness in AlAs/GaAs quantum wells characterized by the mobility of two-dimensional electrons”, Surface Science, vol. 196, No. 1-3, pp. 365-366 (1988).
  • K. Hirakawa, and H. Sakaki: “Hot-electron transport in selectively doped n-type AlGaAs/GaAs heterojunctions”, Journal of Applied Physics, vol. 63, No. 3, pp. 803-808 (1988).
  • H. Sakaki, J. Motohisa, and K. Hirakawa: “Roles of low field mobility and its carrier concentration dependences in high electron mobility transistors and other field effect transistors”, IEEE Electron Device Letters, vol. EDL-9, No. 3, pp. 133-135 (1988).
  • J. Wakabayashi, S. Sudou, S. Kawaji, K. Hirakawa, and H. Sakaki: “Effects of the gate bias on the activation energies of the fractional quantum Hall effect”, Surface Science, vol. 196, No. 1-3, pp. 236-241 (1988).
  • T. Hiramoto, K. Hirakawa, Y. Iye, and T. Ikoma: “One-dimensional GaAs wires fabricated by focused ion beam implantation”, Applied Physics Letters, vol. 51, No. 20, pp. 1620-1622 (1987).
  • H. Sakaki, T. Noda, K. Hirakawa, M. Tanaka, and T. Matsusue: “Interface roughness scattering in GaAs/AlAs quantum wells”, Applied Physics Letters, vol. 51, No. 23, pp. 1934-1936 (1987).
  • J. Wakabayashi, S. Sudou, S. Kawaji, K. Hirakawa, and H. Sakaki: “Second activation energy in the fractional quantum Hall effect”, Journal of the Physical Society of Japan, vol. 56, No. 9, pp. 3005-3008 (1987).
  • K. Hirakawa, and H. Sakaki: “Energy relaxation of two-dimensional electrons and the deformation potential constant in selectvely doped AlGaAs/GaAs heterojunctions”, Proceedings of the 18th Intn’l Conf. on the Physics of Semiconductors, World Scientific, vol. 1, pp. 461-464 (1987).
  • J. Wakabayashi, S. Sudou, S. Kawaji, K. Hirakawa, and H. Sakaki: “Activation energies of the 2/3 fractional quantum Hall effect in a GaAs/AlGaAs heterostructure with a backside gate”, Proceedings of the 18th Intn’l Conf. on the Physics of Semiconductors ’86 vol. 1, World Scientific, pp. 425-428 (1987).
  • K. Hirakawa, T. Noda, and H. Sakaki: “Interface roughness in AlAs/GaAs quantum wells characterized by the mobility of two-dimensional electrons”, The 7th International Conference on Electronic of Two-Dimensional System (1987).
  • T. Hiramoto, K. Hirakawa, and T. Ikoma: “Quasi-one-dimensional planar GaAs wires fabricated by focused ion beam implantation”, The 14th International Symposium on Gallium Arsenide and Related Compounds (1987).
  • T. Hiramoto, K. Hirakawa, and T. Ikoma: “Fabrication of one-dimensinal GaAs wires by focused ion beam implantation”, Japan-USA Seminar on Focused Ion Beam Technoligy and Applications (1987).
  • K. Hirakawa, and H. Sakaki: “Energy relaxation of two-dimensional electrons and the deformation potential constant in selectively doped AlGaAs/GaAs heterojunctions”, Applied Physics Letters, vol. 49, No. 14, pp. 889-891 (1986).
  • K. Hirakawa, and H. Sakaki: “Mobility of the two-dimensional electron gas at selectively doped n-type AlxGa1-xAs/GaAs heterojunctions with controlled electron concentrations”, Physical Review, vol. B33, No. 12-I, pp. 8291-8303 (1986).
  • K. Hirakawa, H. Sakaki, and J. Yoshino: “Electron concentration dependence of the two-dimensional electron mobilities in modulation doped AlGaAs/GaAs heterostructures”, Surface Science, vol. 170, pp. 440-444 (1986).
  • K. Inoue, H. Sakaki, J. Yoshino, and K. Hirakawa: “Subband structures of high mobility electrons in selectively doped AlGaAs/GaAs/AlGaAs double heterojunction FET system”, Surface Science, vol. 174, pp. 382-386 (1986).
  • T. Furuta, K. Hirakawa, J. Yoshino, and H. Sakaki: “Splitting of photoluminescence spectra and negative differential resistance caused by the electric field induced resonant coupling of quantized levels in GaAs-AlGaAs multi-quantum well structures”, Japanese Journal of Applied Physics, vol. 25, No. 2, pp. L151-L154 (1986).
  • K. Inoue, H. Sakaki, J. Yoshino, and K. Hirakawa: “Subband structures of high mobility electrons in selectively doped AlGaAs/GaAs/AlGaAs double heterojunction FET system”, Surface Science, vol. 174, pp. 382-386 (1985).
  • K. Hirakawa, H. Sakaki, and J. Yoshino: “Mobility modulation of the two-dimensional electron gas via controlled deformation of the electron wave function in selectively doped AlGaAs-GaAs heterojunctions”, Physical Review Letters, vol. 54, No. 12, pp. 1279-1282 (1985).
  • K. Hirakawa, H. Sakaki, and J. Yoshino: “SUMMARY ABSTRATCT: Electron concentration in N-AlGaAs/GaAs heterojunction field effect transistors and its dependence on spacer layer thickness”, Journal of Vacuum Science and Technology, vol. B3, No. 2, pp. 798-799 (1985).
  • K. Hirakawa, H. Nakamura, and M. Aoki: “Crystal growth of CuGaS2 from Te, Te-Cu, and Te-Cu-S solutions”, Japanese Journal of Applied Physics, vol. 24, No. 3, pp. 265-279 (1985).
  • K. Hirakawa, H. Sakaki, and J. Yoshino: “Concentration of electrons in selectively doped GaAlAs/GaAs heterojunction and its dependence on spacer-layer thickness and gate electric field”, Applied Physics Letters, vol. 45, No, 3, pp. 253-255 (1984).
  • H. Sakaki, K. Hirakawa, J. Yoshino, S. P. Svensson, Y. Sekiguchi, T. Hotta, S. Nishi, and N. Miura: “Effects of electron heating on the two-dimensional magnetotransport in AlGaAs/GaAs heterostructures”, Surface Science, vol. 142, No. 1-3, pp. 306-313 (1984).