Electron Transport in InAs-InAlAs Core-Shell Nanowires

TL;DR

This study demonstrates that epitaxial InAlAs shells improve electron mobility in InAs nanowires by reducing surface states and impurity scattering, especially at low temperatures.

Contribution

It provides experimental evidence that InAlAs shell growth enhances surface passivation and electron mobility in InAs nanowires.

Findings

Mobility increases monotonically with decreasing temperature in passivated nanowires.

Unpassivated nanowires show a mobility turnover at low temperatures.

Surface passivation reduces ionized impurity scattering.

Abstract

Evidence is given for the effectiveness of InAs surface passivation by the growth of an epitaxial InAlAs shell. The electron mobility is measured as a function of temperature for both core-shell and unpassivated nanowires, with the core-shell nanowires showing a monotonic increase in mobility as temperature is lowered, in contrast to a turnover in mobility seen for the unpassivated nanowires. We argue that this signifies a reduction in low temperature ionized impurity scattering for the passivated nanowires, implying a reduction in surface states.