Photoluminescence properties and DFT simulations of the Cr ion-implanted (100)-oriented β-Ga2O3 single crystals

Abstract

Beta-gallium oxide (β-Ga2O3) with tunable optical and electrical properties has great potential in power metal-semiconductor devices. In this work, (100)-oriented β-Ga2O3 single crystals were implanted with 190 keV Cr ions at different fluencies, and their photoluminescence, band structures, and electronic properties have been studied in detail. Our results clearly show that ion implantation-induced lattice damage could be recovered and the implanted Cr ions in (100)-oriented β-Ga2O3 can be activated to produce NIR (R-lines and broadband) emissions after the post-implantation annealing at 900 °C. Temperature-dependent photoluminescence (TDPL) measurements indicate that the increasing temperature could lead to weakness and redshifts of the R-lines emissions centered at about 692 nm, while the broadband emission centered at about 713 nm enhanced because of a higher thermal occupation at the 4T2 state than at the 2E state. Results from Density functional theory (DFT) calculations demonstrate that the Ga atom’s replacements with Cr atoms could occur at the tetrahedral or octahedral sites of the lattices, which allows the Cr atoms to be activated to act as the NIR emission centers.