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A type of semiconductor heterostructure fabricated by zinc-oxide films deposited on silicon substrates is investigated. The current-voltage characteristics under dark or illumination were determined. It is indicated that the sample is likely a semiconductor junction, and this structure generates an obvious photovoltaic effect. Spectral responses of photovoltage, cathodotoluminescence and excitation spectra at room temperature were employed to study the structural properties and the mechanism generating photovoltaic effect of the samples. The energy level and the process of electron transition in the ZnO film have also been deduced.

We report the observation of the cathode-ray (CR) pumped ultraviolet (UV) super-radiation luminescence in ZnO thin film at room temperature (RT). The dependence of UV (peak at about 390 nm) and green (peak at about 520 nm) luminescent peaks in ZnO thin film under CR excitation on excitation electron beam current has been investigated. With the increase of the density of excitation electron beam current, green peak relatively decreases and UV peak increases, resulting in a change of the luminescent color from green to blue-purple. The green peak intensity increases sublinearly with the increase of the electron beam current density and saturates at a relatively low density of electron beam current. But the intensity of 390 nm UV peak increases superlinearly with the increase of the electron beam current density. This is a UV super-radiation luminescence of exciton in ZnO under high density pump. In this paper, three-dimensional atomic force microscope images of the surface of unannealled and annealled ZnO films are given.

The cathodoluminescence of ZnO films deposited on Si substrates by reactive dc sputtering is investigated. Apart from the characteristic green emission band (522 nm) of ZnO, an ultraviolet (392 nm) band and a blue (430-460 nm) band have been observed. The x-ray diffraction and cathodoluminescent spectra reveal the dependences of the luminescence on the preparation conditions and crystallinity of the ZnO films.