Temperature-dependent electron mobility in InAs nanowires

TL;DR

This study investigates how electron mobility in InAs nanowires varies with temperature, revealing a peak around 30-50 K and decline at higher temperatures due to surface scattering and subband effects, supported by experimental and simulation data.

Contribution

It provides a detailed analysis of temperature-dependent mobility in InAs nanowires, combining transport measurements with finite-element simulations to elucidate scattering mechanisms.

Findings

Mobility peaks around 30-50 K and decreases at higher temperatures.

Coulomb scattering from surface states explains the mobility behavior.

Higher radial subbands and interband scattering influence mobility at elevated temperatures.

Abstract

Effective electron mobilities are obtained by transport measurements on InAs nanowire field-effect transistors at temperatures ranging from 10-200 K. The mobility increases with temperature below ~ 30 - 50 K, and then decreases with temperature above 50 K, consistent with other reports. The magnitude and temperature dependence of the observed mobility can be explained by Coulomb scattering from ionized surface states at typical densities. The behaviour above 50 K is ascribed to the thermally activated increase in the number of scatterers, although nanoscale confinement also plays a role as higher radial subbands are populated, leading to interband scattering and a shift of the carrier distribution closer to the surface. Scattering rate calculations using finite-element simulations of the nanowire transistor confirm that these mechanisms are able to explain the data.