Optical performance of europium-doped β gallium oxide PVD thin films

摘要

β-Gallium oxide is a wide bandgap material that is used in many electronic devices owing to its ultra wide bandgap of ～ 5 eV. It is commonly doped with rare earth metals like europium to improve its electronic and photolumines-cence properties. However, the effect of doping concentration on particularly the optical properties has not been clearly reported yet. Here the aim was to dope β gallium oxide with different concentrations of europium. Therefore europium and gallium oxide were co-sputtered to get varying concentrations of europium in β gallium oxide structure. The doping concentration varied from 4.6 to 10.1 mole% of europium. Their microstructure and phase was studied by SEM and XRD, respectively and their optical performance was studied using UV-Vis spectrophotometer. The optical bandgap of β gallium oxide was found to decrease due to doping with europium. Although the transmittance increased drastically with increase in doping concentration from 4.6 to 10.1%, their bandgap was independent of the dopant concentration. In consultation with the binary phase diagram and photoluminescence of the thin films, the optimal dopant concentration in β gallium oxide was found to be around 10% Eu.