Self-assembled semiconductor quantum dots (QDs) are often called “artificial atoms” and manifest novel physics that originate from quantized electron orbitals and spins. In 2005, we discovered a remarkable feature that, when a single InAs QD is touched by 2 metal electrodes with a nanogap, it behaves as a single electron transistor (SET) (M. Jung, K. Hirakawa, et al., Appl. Phys. Lett., 86, 033106 (2005)). We are working on novel physics and device applications of such semiconductor quantum dot/metal electrode junctions. Particularly, we are making efforts on terahertz dynamics of QDs, spin-correlated transport, and novel electron transport induced by ferromagnetic/superconducting electrodes. Recently, we are working also on the site- and shape-controlled growth of QDs.

Topics

• Obervation of single-electron terahertz photovoltaic effect in quantum dots
• Probing manybody quantum states in single InAs quantum dots: terahertz and tunneling spectroscopy
• Terahertz intersublevel transition spectroscopy of single InAs quantum dots
• Control of electronic states in quantum dots by using ionic liquid gating
• Terahertz photon-assisted tunneling in quantum dots
• Site- and shape-controlled growth of InAs quantum dots