Crystalline characteristics and solar-blind photodetecting performances of β-Ga2O3 film grown on silicon thermal oxide wafer using an EBV method

The fabrication of Ga2O3 film solar blind photodetectors on silicon thermal oxide wafers using an electron beam evaporation technique is reported in this work. The crystalline structure of the Ga2O3 film was varied by applying variant annealing temperatures from 600 to 1000 °C. The effect of annealing temperature on the crystalline structure, surface morphology and optical properties of the Ga2O3 films was analyzed using a couple of sophisticated techniques including X-ray diffraction, Raman spectroscopy, scanning electron microscopy, spectroscopic ellipsometry and ultraviolet-visible spectroscopy. The as-deposited films were found to be amorphous. However, all the annealed films were observed and it was found that they were made of phase-pure β-Ga2O3 with an increasingly higher crystal quality of the (400) orientation as the annealing temperature increased. The detailed photoresponse measurements showed that, among all the films, the 800 °C annealed film displays the best comprehensive photoresponse characteristic with the highest Iphoto/Idark ratio of 5.15 × 103 as well as rapider response times of 0.59 s for the rise phase and 0.15 s for the decay phase. The results in this work reveal that β-Ga2O3 films grown on the thermal oxide wafer can realize the combination of low cost and high performance for further applications in solar-blind ultraviolet photodetectors.