LAUSR

Abstract The influence of oxygen partial pressure and annealing on the properties of thin films of β-Ga2O3 grown by pulsed laser deposition were studied. The Ga2O3 samples were deposited at a substrate temperature of 250 °C at an oxygen pressure of 0–50 mTorr and then annealed at a temperature of 600 °C. We observed the crystallinity of Ga2O3 enhanced with annealing and with increasing oxygen pressure. The full width at half maximum of annealed β -Ga2O3 ( 4 ¯ 01 ) peaks decreased, corresponding to the grain size increasing from 6.76 nm to 11.25 nm. The conductivity of the obtained, as-grown Ga2O3 films increased with oxygen pressure from 2.1 to 7.9 mScm−1. As a result, the conductance and the energy band gap of β-Ga2O3 without annealing were controlled by the oxygen partial pressure. This was attributed to the oxygen vacancies, based on the composition ratio between O and Ga ions. These results clearly showed that the energy band gap and conductance of β-Ga2O3 thin films could be controlled in such a way that could be utilized for high-performance photo-electronic devices.