Effect of different substrates on Si and Ta co-doped Ga2O3 films prepared by pulsed laser deposition

Abstract In this study, the structure, morphology, electrical and optical properties of Si and Ta co-doped gallium oxide (Ga2O3) films deposited on (1 0 0) Ga2O3, (0 0 0 1) sapphire and quartz substrates by pulsed laser deposition are analyzed. The Si and Ta co-doped Ga2O3 film on Ga2O3 substrate possessed the best crystal quality with a high carrier concentration of 1.12 × 1020 cm−3 and a conductivity of 2.13 S·cm−1 compared to the sapphire and quartz substrates. The Si and Ta co-doped Ga2O3 films on different substrates exhibited high transmittance (>73%) above 300 nm and smooth film surface. The optical gap of Si and Ta co-doped Ga2O3 films on Ga2O3, sapphire and quartz substrates decreases from 4.89 to 4.85 eV, and the corresponding Urbach energy increases from 0.396 to 0.704 eV, so the homoepitaxial Si and Ta co-doped Ga2O3 film possess the best quality.