Large critical field of Li-doped NiO investigated by p⁺-NiO/n⁺-Ga₂O₃ heterojunction diodes

Abstract Critical electric fields (E C) of lithium-doped p+-nickel oxide (NiO) were investigated by the capacitance (C)–voltage (V) and current (I)–V measurements using p+-NiO/n+-gallium oxide (Ga2O3) heterojunction diodes. The E C was estimated by device simulations using the net acceptor concentrations (N A) obtained from C–V measurements and breakdown voltages obtained from reverse I–V characteristics. The E C of NiO depended on the N A of the NiO and ranged from 5.4 to 10.1 MV cm−1. Large E C was obtained for high N A. NiO was confirmed to be one of the promising p-type oxides to realize high-power p-n heterojunction devices with Ga2O3 due to the high E C.