Electrical transport in C-doped GaAs nanowires: surface effects

TL;DR

This study investigates how surface effects influence electrical transport properties in Carbon-doped GaAs nanowires, revealing that surface passivation can significantly enhance mobility and affect carrier diffusion.

Contribution

It provides direct experimental evidence of surface effects on resistivity and mobility in doped GaAs nanowires, highlighting the impact of surface passivation.

Findings

Surface passivation increases mobility up to 30 cm^2/(V*s).

Depletion regions caused by Fermi level pinning affect transport.

Minority carrier diffusion length can reach 190 nm in passivated nanowires.

Abstract

The resistivity and the mobility of Carbon doped GaAs nanowires have been studied for different doping concentrations. Surface effects have been evaluated by comparing upassivated with passivated nanowires. We directly see the influence of the surface: the pinning of the Fermi level and the consequent existence of a depletion region lead to an increase of the mobility up to 30 cm^2/(V*s) for doping concentrations lower than 3*10^18 cm^-3. Electron beam induced current measurements show that the minority carrier diffusion path can be as high as 190 nm for passivated nanowires.