Counting statistics in an InAs nanowire quantum dot with a vertically coupled charge detector

A gate-defined quantum dot (QD) in an InAs nanowire is fabricated on top of a quantum point contact realized in a two-dimensional electron gas. The strong coupling between these two quantum devices is used to perform time-averaged as well as time-resolved charge detection experiments for electron flow through the quantum dot. We demonstrate that the Fano factor describing shot noise or time-correlations in single-electron transport depends in the theoretically expected way on the asymmetry of the tunneling barriers even in a regime where the thermal energy k(B)T is comparable to the single-particle level spacing in the dot. (C) 2012 American Institute of Physics. [doi:10.1063/1.3687198]