The study of electrical characteristics of heterojunction based on ZnO nanowires using ultrahigh-vacuum conducting atomic force microscopy

The electrical performances of the heterojunction of n-ZnO nanowires with p-Si substrate at the nanometer scale have been characterized using an ultrahigh-vacuum conducting atomic force microscopy. Compared with the expected values of 1.0–2.0 reported in p-n junction in the previous studies, the abnormally high diode ideality factor (⪢2) was obtained. It elucidates that a ZnO–Si p-n junction can be modeled by a series of diodes, the actual ZnO–Si junction diode and two Schottky diodes at the metal/ZnO and metal/Si junctions. The tunneling across p-n junction would also play a role in the externally measured high ideality factor.