Fabrication and electrical characterization of nanocrystalline ZnO/Si heterojunctions

摘要

Nanocrystalline zinc oxide (nc-ZnO) films were prepared by a sol-gel process on p-type single-crystalline Si Substrates to fabricate nc-ZnO/p-Si heterojunctions. The Structure and morphology of ZnO films on Si substrates, which were analyzed by X-ray diffraction (XRD) spectroscopy and atomic force microscopy (AFM), showed that ZnO films consisted of 50-100 nm polycrystalline nanograins with hexagonal wurtzite structure. The electrical transport properties of the nc-ZnO/p-Si heterojunctions were investigated by temperature-dependent current-voltage (I-V) measurements and room temperature capacitance-voltage measurements. The temperature-dependent I-V characteristics revealed that the forward conduction was determined by multi-step tunneling Current, and the activation energy of saturation current was about 0.26 eV. The 1/C-2-V plots indicated the junction was abrupt and the junction built-in potential wits 1.49 V at room temperature. (c) 2005 Elsevier B.V. All rights reserved.