Temperature dependence of red luminescence in pure β-Ga2O3: An estimation of electron-phonon interaction

Abstract

Electron-Phonon (e-ph) interactions have been studied from temperature dependent photoluminescence (PL) of red emission line originating from Cr3+ ions unintentionally present in pure β-Ga2O3 powder. Excitonic recombination is determined to be the nature of observed PL at low temperatures for both R1 and R2 lines. On the basis of mean phonon temperature, obtained from the temperature dependence of PL peak energy and line width of R1 and R2 lines, it is found that the low frequency phonon modes belonging to translation and liberation of GaO4 tetrahedrons chain and medium frequency phonon modes belonging to deformation of GaO6 octahedrons and GaO4 tetrahedrons mainly interact with the carriers for R1 and R2 lines respectively. A carrier transfer from R1 line to R2 line with an increase in the temperature has been noted at low temperature region (40 K–150 K). Our results are helpful in understanding the physical processes behind the e-ph interactions occurring in β-Ga2O3.