Towards high mobility InSb nanowire devices

TL;DR

This study systematically measures and optimizes the electron mobility in InSb nanowires at low temperatures, achieving some of the highest reported values and identifying surface adsorption as a key limiting factor.

Contribution

It introduces a model for accurate mobility extraction in InSb nanowires and demonstrates reproducibility of high mobility values, highlighting surface effects as a mobility limiter.

Findings

Achieved a field effect mobility of ~2.5×10^4 cm^2/Vs.

Mobility is limited by surface adsorption of molecules.

Reproducible high mobility values among nanowires.

Abstract

We study the low-temperature electron mobility of InSb nanowires. We extract the mobility at 4.2 Kelvin by means of field effect transport measurements using a model consisting of a nanowire-transistor with contact resistances. This model enables an accurate extraction of device parameters, thereby allowing for a systematic study of the nanowire mobility. We identify factors affecting the mobility, and after optimization obtain a field effect mobility of $\sim2.5\mathbin{\times}10^4$ cm$^2$/Vs. We further demonstrate the reproducibility of these mobility values which are among the highest reported for nanowires. Our investigations indicate that the mobility is currently limited by adsorption of molecules to the nanowire surface and/or the substrate.