一种新型的高频半导体量子点单电子泵

除了直流负电压外，还在浅法刻蚀出的GaAs/AlGaAs量子线上的两个金属指形门上分别叠加两个相位相差π的正弦信号，从而对形成量子点的两个势垒作不等幅调制.在无源漏偏压的情况下，通过周期形成的量子点实现了单电子的搬运.由于新的半导体量子点单电子泵不是依赖库仑阻塞效应通过隧穿进行单电子输运，因此，该器件就不会受到固定隧穿时间引起的低工作频率限制.在1.7K温度下，频率达到3GHz仍然可以观测到量子化电流平台，对应的电流值达到0.5nA量级.这种新器件提供了实现高速度、高精度搬运单电子的另一种可能途径. 关键词： 单电子输运 单电子旋转门 单电子泵 量子化电流平台

Single electron pumping at higher frequency in a novel semiconductor-based quantum dot device

The π-shift sinusoidal signals with different amplitudes applied directly to the two metallic finger gates on a shallow etched GaAs/AlGaAs quantum wire，tune unequally the two barriers of a static quantum dot induced by applying negative dc voltages on these two finger gates. Single electrons are transported through a periodically formed quantum dot without source-drain bias. Since single electron pumping in the novel semiconductor-based quantum dot device does not rely on Coulomb blockade of tunnelling，the device can not be limited to much lower frequency by the fixed tunneling time constant. Current plateaus due to single electron transport can be observed at 1.7K with frequencies up to 3GHz and a current level of 0.5nA. This novel device represents another possible path in the realization of a high current high accuracy quantum standard for electrical current，and also provides another means for high specd high accuracy transport of single electrons.