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 -Ga _2 O _3 microwire are systematically investigated. The β -Ga _2 O _3 microwire that is (020)-oriented shows 14 Raman peaks, with all their FWHM narrower than those of (100)-oriented β -Ga _2 O _3 bulk single crystal. As the temperature increases from 80 to 300 K, 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 and the quantitative analysis reveals that there exists quite strong EPC in β -Ga _2 O _3 microwire and the Huang–Rhys factor is up to Sʹ ≈ 14.

Keywords

• β-Ga2O3 microwire
• lattice vibration
• electron-phonon coupling
• Raman spectroscopy
• photoluminescence