A Roadmap for Controlled and Efficient n-type Doping of Self-assisted GaAs Nanowires Grown by Molecular Beam Epitaxy

TL;DR

This paper demonstrates a controlled method for n-type doping of GaAs nanowires using Te donors during molecular beam epitaxy, achieving high carrier densities and characterizing their electrical and optical properties.

Contribution

It introduces a precise growth process for Te-doped GaAs nanowires with high carrier density, overcoming doping challenges due to silicon's amphoteric nature.

Findings

Achieved carrier density up to 10^20 electrons/cm^3

Established growth conditions for effective Te incorporation

Correlated doping levels with electrical and optical properties

Abstract

N-type doping of GaAs nanowires has proven to be difficult because the amphoteric character of silicon impurities is enhanced by the nanowire growth mechanism and growth conditions. The controllable growth of n-type GaAs nanowires with carrier density as high as 1020 electron/cm3 by self-assisted molecular beam epitaxy using Te donors is demonstrated here. Carrier density and electron mobility of highly doped nanowires are extracted through a combination of transport measurement and Kelvin probe force microscopy analysis in single-wire field-effect devices. Low-temperature photoluminescence is used to characterize the Te-doped nanowires over several orders of magnitude of the impurity concentration. The combined use of those techniques allows the precise definition of the growth conditions required for effective Te incorporation.