Ultrawide-Bandgap p-n Heterojunction of Diamond/β-Ga<sub>2</sub>O<sub>3</sub> for a Solar-Blind Photodiode
Hyun Kim, С. А. Тарелкин, A. Y. Polyakov, S. Yu. Troschiev, Sergey Nosukhin, М. С. Кузнецов, Jihyun Kim
Abstract
The potential of ultrawide-bandgap (UWBG) semiconductors has not been fully explored because of the difficulty of forming a p-n homojunction. In this study, a mixed-dimensional UWBG p-n heterojunction composed of a p-type diamond substrate and an n-type exfoliated β -Ga 2 O 3 nanolayer has been demonstrated via a van der Waals interaction; this type of structure does not suffer from lattice mismatch. Rectifying current-voltage characteristics with a rectification ratio exceeding 10 7 were obtained with a high reverse hard breakdown voltage of 135 V. This UWBG p-n heterojunction diode exhibited good thermal stability at elevated temperatures, retaining its high rectification ratio and low reverse leakage current. Excellent photoresponse characteristics, including responsivity (12 A W −1 ), rejection ratio (8.5 × 10 3 ), photo-to-dark-current ratio (3900), and fast response/decay characteristics, were observed from the diamond/ β -Ga 2 O 3 p-n heterojunction photodiode, showing no persistent photoconductivity. The mixed-dimensional p-n heterojunction diode based on two UWBG semiconductors (p-type diamond and n-type β -Ga 2 O 3 ) can be used as a robust building block in next-generation power electronics and solar-blind optoelectronics.