Gate-defined quantum dot single electron pump

We report single electron pumping through a metal gate defined quantum dot (QD) fabricated on a GaAs/AlGaAs 2-dimensional electron gas (2DEG) system. The quantum dot used for pumping is uniquely designed to have larger subband energy spacings than those of a conventional quantum dot. Several quantized current steps were observed at liquid helium temperature when the pump was operated at 100 MHz of pumping frequency. The flatness of the current plateaus was measured with different subband energy spacings. It was found that the flatness of the plateau is influenced by the subband energy spacings of the QD.