Ultra-high mobility two-dimensional electron gas in a SiGe/Si/SiGe quantum well

TL;DR

This paper reports the creation of a high-mobility two-dimensional electron gas in a SiGe/Si/SiGe quantum well, achieving record mobility and revealing insights into scattering mechanisms with potential implications for silicon-based electronic devices.

Contribution

The study demonstrates a significantly higher electron mobility in SiGe/Si/SiGe quantum wells using SiO insulators, and identifies the dominant scattering mechanisms affecting conductivity.

Findings

Maximum mobility of 240 m^2/Vs achieved

Reduced threshold voltages with SiO insulator

Linear temperature dependence indicates short-range scattering

Abstract

We report the observation of an electron gas in a SiGe/Si/SiGe quantum well with maximum mobility up to 240 m^2/Vs, which is noticeably higher than previously reported results in silicon-based structures. Using SiO, rather than Al_2O_3, as an insulator, we obtain strongly reduced threshold voltages close to zero. In addition to the predominantly small-angle scattering well known in the high-mobility heterostructures, the observed linear temperature dependence of the conductivity reveals the presence of a short-range random potential.