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

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).