| The Si/ZnO heterojunction has a very strong photovoltaic effect, and thus the growth of zinc oxide on the silicon and the luminescence properties of Si/ZnO have a relatively mature theoretical, but the charge transport mechanism of the Si/ZnO heterojunction is relatively small. Under the same conditions, the ZnO nanorod array films has excellent optical properties and electron transport capacity, and thus studying the surface photovoltaic properties of silicon-based ZnO nanorod arrays have very great significance for the design and preparation of optoelectronic devices.The surface photovoltage spectrum (SPS) technique with its high sensitivity and high spatial resolution provides a well-established contactless and nondestructive method for semiconductor characterization, which relies on the analysis of the photo-induced change in surface voltage. Moreover, the energy levels, the conduction type and the charge transport mechanism of semiconductors can be obtained by SPS. Thus, the SPS based the Kelvin Probe technology and MIS structure can be widely used as an efficient tool for characterizing the surface photovoltage properties of semiconductors.In this paper, ZnO nanorod arrays were prepared by seed-assisted chemical bath deposition, in which the ZnO films prepared by magnet on sputtering were used as the seed layers on the P-Si (100) substrate. ZnO nanorod array were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD) and photoluminescence (PL) spectroscopy. The results show that ZnO nanorod with very few defects are basically along the c-axis growth, and have good UV light-emitting characteristics. The SPS based the Kelvin Probe technology and MIS structure was employed to investigate the surface photovoltage behavior of ZnO nanorod array. The surface photovoltage and its time-resolved evolution process are used to determine the energy level structure of the ZnO nanorod array. As a result, the life level of the photoelectron in Si-based ZnO nanorod arrays is very few. And the charge transfer of the Si/ZnO heterojunction is analyzed, and the different mechanism of charge transport and separation in the sample are determined. These provide a theoretical reference for the production of silicon-based ZnO nanorod devices. |
