Electrical manipulation and read-out of quantum states in zero-dimensional (0D) nanostructures by nano-gap metal electrodes is expected to bring about innovation in quantum information processing. However, electrical tunability of the quantum states in 0D nanostructures is limited by the screening of gate electric fields. Here, we demonstrate a new way to realize wide-range electrical modulation of quantum states of single self-assembled InAs quantum dots (QDs) with a liquid-gated electric-double-layer (EDL) transistor geometry. The efficiency of EDL gating is 6-90 times higher than that of the conventional solid-gating. The quantized energy level spacing is modulated from ~15 meV to ~25 meV and the electron g-factor is electrically tuned over a wide range. Such a field effect tuning can be explained by the modulation in the confinement potential of electrons in the QDs. The EDL gating on the QDs also provides potential compatibility with optical manipulation of single electron charge/spin states.
