Rectification in mesoscopic AC-gated semiconductor devices

TL;DR

This paper investigates the complex rectified currents in mesoscopic AC-gated semiconductor devices, models their behavior considering stray impedances, and evaluates their impact on tunable-barrier electron pumps for metrological standards.

Contribution

It provides a comprehensive model of rectification effects in AC-gated devices and demonstrates their minimal impact on high-precision electron pumps.

Findings

Rectified currents vary complexly with bias and gate voltages.

Model aligns well with experimental data across frequencies.

Rectified currents are negligible compared to pumped current, supporting metrological applications.

Abstract

We measure the rectified dc currents resulting when a 3-terminal semiconductor device with gate-dependent conductance is driven with an ac gate voltage. The rectified currents exhibit surprisingly complex behaviour as the dc source-drain bias voltage, the dc gate voltage and the amplitude of the ac gate voltage are varied. We obtain good agreement between our data and a model based on simple assumptions about the stray impedances on the sample chip, over a wide frequency range. This method is applicable to many types of experiment which involve ac gating of a non-linear device, and where an undesireable rectified contribution to the measured signal is present. Finally, we evaluate the small rectified currents flowing in tunable-barrier electron pumps operated in the pinched-off regime. These currents are at most $10^{-12}$ of the pumped current for a pump current of 100 pA. This result is encouraging for the development of tunable-barrier pumps as metrological current standards.