We fabricate and characterize a radio-frequency semiconductor point-contact electrometer (RF-PC) analogous to radio-frequency single-electron transistors [RF-SETs, see Science {\bf 280}, 1238 (1998)]. The point contact is formed by surface Schottky gates in a two-dimensional electron gas (2DEG) in an AlGaAs/GaAs heterostructure. In the present setup, the PC is operating as a simple voltage-controlled resistor rather than a quantum point contact (QPC) and demonstrates a charge-sensitivity about 2×10−1e/Hz at a bandwidth of 30kHz without the use of a cryogenic RF preamplifier. Since the impedance of a typical point-contact device is much lower than the impedance of the typical SET, a semiconductor-based RF-PC, equipped with practical cryogenic RF preamplifiers, could realize an ultra-fast and ultra-sensitive electrometer.
@article{arxiv.0708.2473,
title = {Radio-frequency point-contact electrometer},
author = {Hua Qin and David A. Williams},
journal= {arXiv preprint arXiv:0708.2473},
year = {2007}
}
Comments
11 pages, 3 figures. This article is identical to the version that appeared in Appl. Phys. Lett. 88, 203506 (2006). The published version can be found at http://apl.aip.org/