High performance UV Photodetector Based On βGa2O3 /GaN Heterojunction Fabricated by a Reversed Substitution Growth Method

A wide band gap semiconductor heterojunction of $\beta$Ga2O
3
/GaN is fabricated by thermal oxidizing reversed substitution growth method. XRD shows the Ga2O
3
is $\beta-$phase with (-201) preferred orientation. XPS demonstrates that the Fermi level is 0.2 eV lower than the central level of the band gap, indicating that the dominant carriers are holes. Based on this heterostructure, an UV photodetector of graphene/$\beta-$ Ga2O
3
/GaN p-i-n heterojunction with high detectivity is constructed. The device shows a rapid response speed and large I$\mathrm{i}_{\mathrm{i}\mathrm{g}\mathrm{h}\mathrm{t}}$/$\mathrm{I}_{\mathrm{d}\mathrm{a}\mathrm{r}\mathrm{k}}$ ratio of over 1$0^{6}$.