Preparation of high performance Ga2O3 based ultraviolet photodetector by CVD

Abstract

Here, β-Ga2O3 films have been grown on c-Al2O3 and p-GaN substrates by chemical vapor deposition method to fabricate solar-blind ultraviolet photodetectors with MSM-type planar structure and pn-junction vertical structure respectively. The β-Ga2O3 films grown with domain growth mode exhibit high crystallinity and flat surface, so the fabricated MSM-type photodetector shows spectral peak responsivity of 1.83 A/W at 254 ​nm and photo-to-dark current ratio of 104 under 25 ​V bias with 20% oxygen fraction and 120 sccm flow rate. On this basis, the constructed vertical structured β-Ga2O3/p-GaN heterojunction photodetector shows peak responsivity of 1.99 A/W under 25 ​V for the junction effect between β-Ga2O3 and p-GaN. Meanwhile, spectral responsivity peak of 1.36 ​× ​10−4 A/W at 0V claims significant self-powered effect induced by build-in electric field between β-Ga2O3 and p-GaN. These results confirm that high performance β-Ga2O3 solar-blind ultraviolet photodetectors can be obtained by simple chemical vapor deposition method.