Study on photoelectric properties of Si supported ZnO

The ZnO films were deposited on p-Si(100) substrate to show the stoichiometric coefficient ratio of Zn and O is greater than 1:1, indicating the existence of oxygen vacancies in ZnO films, moreover, the oxidation state of Si2p shows the formation of silicon oxide in the vicinity of Si/ZnO interface (ZnO side), which result from Si diffusion into ZnO film. Different models of Si supported ZnO were constructed based on experimental results to study its photoelectric properties, the numerical investigations reveal that Fermi level of ZnO:Si, ZnO:Si-int, and ZnO-VO all move to conduction band minimum, which means they are beneficial to n type semiconductor. The dielectric function of ZnO–Si-int moves to the lower energy direction (red shift), the conductivity of which is higher in the range of 3eV∼7eV, and its absorption and reflectivity both are higher with wavelength more than 300 nm; however, the optical properties of ZnO:Si are poor, implying that the degradation of photoelectrical properties of Si/ZnO heterojunction result from Si diffusion in ZnO films.