Photoluminescence study of β-Ga2O3 nanostructures annealed in different environments

Abstract

β-Ga2O3 nanostructures (nanowires, nanoribbons, and nanosheets) were synthesized via vapor transport method on gold coated silicon substrate in N2 ambient and these β-Ga2O3 nanostructures grown on silicon substrates were taken as the starting material to study the effect of annealing in the different environments (oxygen, water vapour, and ammonia solution) on the structural front and photoluminescence (PL) properties. The PL spectra of β-Ga2O3 nanostructures exhibit a UV-blue emission band whose intensity is strongly affected by the annealing in different environments. Annealing modifies the surface of the nanostructures by creating surface states which quench the PL by creating competitive nonradiative paths. This study also indicates the dominance of the formation of water induced surface states over ammonia induced surface states. The irreversible nature of these defects significantly affects the applicability of this system in moist high temperature environments.