Abstract: The grain boundary layer behavior in ZnO/Si heterostucture is investigated. The current–voltage (I –V ) curves, deep level transient spectra (DLTS) and capacitance–voltage (C–V ) curves are measured. The transport currents of ZnO/Si heterojunction are dominated by grain boundary layer as high densities of interfacial states existed. The interesting phenomenon that the crossing of lnI – V curves of ZnO/Si heterojunction at various measurement temperatures and the decrease of its effective barrier height with the decrement of temperature are in contradiction with the ideal heterojunction thermal emission model is observed. The details will be discussed in the following.

Key words: ZnO/Si heterostructure