Fidelity of counting the transferred electrons in a GaAs-based monolithic single-electron pump and transistor system with a charge-lock feedback circuit

Abstract

We developed an electron-counting technique for a self-referenced single-electron quantized current source of a single-electron-pump system and investigated the fidelity of our whole measurement process, including single-electron pumping and electron counting by a single-electron transistor (SET) with a charge-lock feedback loop. The device was fabricated monolithically using a two-dimensional electron system of a GaAs/AlGaAs hetero-junction. In addition to the probability of single-electron transfer, we also measured the current noise spectrum of the SET, from which its charge noise power Sq was derived. The results show that the estimated charge noise of 2.2 ×10−4 e/Hz for a semiconductor-based SET is comparable to that of metallic SETs.