H$_{2}$-diluted precursors for GaAs doping in chemical beam epitaxy

TL;DR

This study demonstrates that H$_{2}$-diluted precursors enable precise control of doping levels in GaAs layers grown by chemical beam epitaxy without affecting their electrical and optical properties.

Contribution

It introduces a method using H$_{2}$-diluted gas precursors for controlled doping in GaAs, with detailed analysis of doping levels and properties.

Findings

Carrier concentrations achieved: 6×10^{17}–1.2×10^{19} cm^{-3} for Si

Carrier concentrations achieved: 9×10^{16}–3.7×10^{20} cm^{-3} for C

Doping levels follow specific power laws with precursor flux

Abstract

A wide range of n- and p-type doping levels in GaAs layers grown by chemical beam epitaxy is achieved using H$_{2}$-diluted DTBSi and CBr$_{4}$ as gas precursors for Si and C. We show that the doping level can be varied by modifying either the concentration or the flux of the diluted precursor. Specifically, we demonstrate carrier concentrations of 6$\times$10$^{17}$-1.2$\times$10$^{19}$ cm$^{-3}$ for Si, and 9$\times$10$^{16}$-3.7$\times$10$^{20}$ cm$^{-3}$ for C, as determined by Hall effect measurements. The incorporation of Si and C as a function of the flux of the corresponding diluted precursor is found to follow, respectively, a first and a fourth order power law. The dependence of the electron and hole mobility values on the carrier concentration as well as the analysis of the layers by low-temperature (12 K) photoluminescence spectroscopy indicate that the use of H$_{2}$ for diluting DTBSi or CBr$_{4}$ has no effect on the electrical and optical properties of GaAs.