All-oxide p-n heterojunction diodes comprising p-type NiO and n-type β-Ga2O3

NiO/beta-Ga2O3 all-oxide p-n heterojunction diodes were fabricated for the first time using p-type NiO epitaxial layers grown on n-type beta-Ga2O3 substrates. The fabricated diodes exhibited good rectifying current-voltage characteristics, with a rectifying ratio greater than 10(8) at +/- 3V. The capacitance-voltage measurements showed that the built-in voltage was 1.4 V. These results were discussed in terms of the energy band diagram of a type-II heterojunction, where the conduction band and valence band discontinuities were estimated to be 2.2 and 3.4 eV, respectively. (C) 2016 The Japan Society of Applied Physics