High mobility two-dimensional electron system on hydrogen-passivated silicon(111) surfaces

TL;DR

This study demonstrates the fabrication of a high-mobility two-dimensional electron system on hydrogen-passivated Si(111) surfaces using a vacuum cavity device, achieving significant electron densities and mobility at cryogenic temperatures.

Contribution

It introduces a novel vacuum cavity device for creating high-quality 2D electron systems on sensitive silicon surfaces, preserving surface integrity and enabling high mobility measurements.

Findings

Electron densities up to 6.5 x 10^{11} cm^{-2}

Peak mobility of ~8000 cm^{2}/V s at 4.2 K

Successful fabrication of a field-effect transistor with preserved surface integrity

Abstract

We have fabricated and characterized a field-effect transistor in which an electric field is applied through an encapsulated vacuum cavity and induces a two-dimensional electron system on a hydrogen-passivated Si(111) surface. This vacuum cavity preserves the ambient sensitive surface and is created via room temperature contact bonding of two Si substrates. Hall measurements are made on the H-Si(111) surface prepared in aqueous ammonium fluoride solution. We obtain electron densities up to $6.5 \times 10^{11}$ cm$^{-2}$ and peak mobilities of $\sim 8000$ cm$^{2}$/V s at 4.2 K.