Investigations on zinc oxide thin films grown on Si (1 0 0) by thermal oxidation

Thin films of ZnO were grown on p-type Si (1 0 0) substrates by thermal oxidation. The in situ growth of the metallic Zn films were thermally oxidized at different temperatures ranging from 300 to 500 °C to yield ZnO thin films. The structural characterization of the thin films was carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The X-ray diffraction measurements show that the films deposited at 500 °C had better crystalline quality than the rest. The electrical transport properties of the ZnO/Si heterojunction were investigated by current–voltage (I–V) and capacitance–voltage (C–V) measurements. The heterojunction exhibited a barrier height, which is consistent with the energy difference between the work functions of Si and ZnO. Complex impedance spectroscopy measurements at temperatures ranging from 50 to 125 °C were performed on these heterojunctions.