Temperature-dependent Raman-active phonon modes and electron−phonon coupling in β-Ga₂O₃ microwire

Abstract

The lattice vibration and electron-phonon coupling (EPC) in β-Ga2O3 microwire are systematically investigated. The β-Ga2O3 microwire that is (020)-oriented shows 14 Raman peaks, with all the full width at half maximum (FWHM) of them narrower than those of (100)-oriented β-Ga2O3 bulk single crystal. As the temperature increases from 80K to 300K, most Raman-active phonon modes are blueshifted, while a few modes are first blueshifted and then redshifted. The photoluminescence mainly originates from the recombination of self-trapping exciton (STE) and the quantitative analysis reveals that there exists quite strong EPC in β-Ga2O3 microwire and the Huang-Rhys factor is up to Sʹ≈14.