Mis-cut direction of substrate effect on the photoresponse characteristic of β-Ga2O3 film

Abstract

β-Ga2O3 epitaxial film was grown on 6° mis-cut angle (toward <112‾0> and <101‾0> directions) c-plane sapphire substrate by metalorganic chemical vapor deposition (MOCVD). The influence of mis-cut sapphire substrate on β-Ga2O3 film and the photoresponse properties of β-Ga2O3 photodetectors were studied. Compared with non-miscut substrates, both mis-cut sapphire substrates can obtain high crystal quality β-Ga2O3 films by reducing the in-plane rotational symmetry and promoting the step flow growth mode. Compared with the mis-cut toward <112‾0> direction, the substrate of mis-cut toward <101‾0> direction showed the highest crystal quality and largest growth rate due to smaller edge step terrace width and large step density. Three β-Ga2O3 photodetectors were fabricated on films grown on the non-miscut and the two mis-cut substrates. The photoresponse characteristics of β-Ga2O3 photodetectors based on sapphire substrate of mis-cut toward <101‾0> direction can reach 65 μA (photocurrent), 3.5 × 103 (Ip-Id/Id) and 3.21 A/W (responsivity, under 254 nm light). These results demonstrate an important guidance to develop the industrialization of β-Ga2O3 materials and devices.