Capacitance-voltage characteristics of ZnO∕GaN heterostructures

Abstract

We have investigated the electrical properties of ZnO∕GaN heterostructures by capacitance-voltage (C-V) measurements. ZnO∕GaN heterostructures are fabricated on Ga-polar GaN templates by plasma-assisted molecular-beam epitaxy. The ZnO∕GaN heterostructures exhibit a plateau region of 6.5V in the C-V curves measured at 10kHz and room temperature. Moreover, it is found that a large electron density is accumulated at the interface of ZnO∕GaN, where the concentration approaches ∼1018cm−3. The distinct C-V characteristics are ascribed to large conduction-band discontinuity at the ZnO∕GaN heterointerface. It is suggested that the ZnO∕GaN heterostructure is a very promising material for the application to heterojunction transistors.