The identification of the dominant donors in low temperature grown InPBi materials

TL;DR

This study combines experimental magnetotransport measurements and first-principles calculations to analyze how bismuth incorporation affects the electrical properties of low-temperature grown InPBi materials, revealing complex defect-related doping behavior.

Contribution

It provides a systematic investigation of Bi effects on InPBi's electrical properties using combined experimental and theoretical approaches, highlighting defect roles.

Findings

Electron concentration decreases then increases with Bi content.

Electron mobility varies inversely with electron concentration.

Phosphorus antisites and vacancies are key donors.

Abstract

Combined with magnetotransport measurements and first-principles calculations, we systematically investigated the effects of Bi incorporation on the electrical properties of the undoped InP1-xBix epilayers with 0<x<2.41%. The Hall-bar measurements reveal a dominant n-type conductivity of the InPBi samples. The electron concentrations are found to decrease firstly as x increases up to x=1.83%, and then increase again with further increasing Bi composition, whiles the electron mobility shows an inverse variation to the electron concentration. First-principle calculations suggest that both the phosphorus antisites and vacancy defects are the dominant donors responsible for the high electron concentration. And their defect concentrations show different behaviors as Bi composition x increases, resulting in a nonlinear relationship between electron concentration and Bi composition in InPBi alloys.