Single electron tunneling effects in a heavily doped n+GaAs quantum dot

摘要

We report the fabrication and the characterization of a singleelectrontransistor made from a thin layer of heavily doped GaAs. Simplewet-etching process followed by an electron beam lithography wasemployed to define the quantum dot and the tunnel barriers. The observeddot diameter was approximately 50 nm and clear drain current oscillationswere observed at the temperatures much higher than 10 K. At lowtemperatures below 8 K, oscillation peaks beat with two different periods,which suggests the existence of an unintentional quantum dot in thechannel layer. The modulated conductance oscillations were analyzed bythe model of two dots connected in series. The Monte-Carlo simulationqualitatively confirms the measured results. Our modelling resultssuggest that the size of the unintentional dot is much larger than the interimpurityspacing.