Single-Gated Single-Electron Transfer in Nonuniform Arrays of Quantum Dots

Single-electron transfer in single-gated one-dimensional quantum dot arrays is investigated statistically from the viewpoint of robustness against parameter fluctuations. We have found numerically that inhomogeneous quantum dot arrays formed in doped nanowires exhibit single-electron transfer over a wide range of parameters. This confirms our frequent experimental observation of single-electron transfer in doped-nanowire field-effect transistors. The most important result in this work is that three-dot arrays with small-large-small dot size distribution always allow single-electron transfer even if dot sizes fluctuate. This structure is, we believe, most promising for fabricating devices with high immunity against structural fluctuations on the nanometer scale. On the basis of these findings, we propose methods to fabricate high-yield single-electron transfer devices.