Observation of discrete dopant potential and its application to Si single-electron devices

Single-electron devices are attractive because of their ultimate capabilities such as single-electron transfer, single-electron memory, single-photon detection and high sensitivity to elemental amount of charge. We studied single-electron transport in doped nanoscale-channel field-effect transistors in which the channel potential is modulated by ionized dopants. These devices work as arrays of quantum dots with dimensions below present lithography limits. We demonstrate the ability of dopant-induced quantum dot arrays to mediate the transfer of individual electrons one at a time (single-electron transfer). We also monitored the actual dopant distribution and observed single dopant potentials using low temperature Kelvin probe force microscopy.