Preparation And Characteristics Of Li-doped Zinc Oxide Thin Film

Zinc oxide is a typical third-generation semiconductor material having a band gapof3.37eV. Exciton binding energy of Zinc oxide is60meV, it belong to II-VIsemiconductors. Zinc oxide has unique characteristics in piezoelectric, electrical andoptical memory, so zinc oxide has broad application prospects in sensors, laser systems,and conductive memory device. Currently doping is an effective way to improve theperformance of zinc oxide thin-film in photoelectric property. In this paper Li-doped ZnOfilms were prepared by magnetron sputtering and study their optical properties andelectrical properties.Li-doped ZnO films are hexagonal structure, with good c-axis orientation. Li-dopedZnO films has good light transmittance in the visible area, it‘s UV absorption edge issteep. Photoluminescence spectra showed that Li-doped ZnO has peak at390nm,408nm,434nm,465nm. Li-doped zinc oxide film is n-type semiconductor, which is due to thelithium into the lattice forming Lizn-Lii donor compound.Studies have shown that increasing annealing temperature and growth temperaturewill help to improve the crystallinity of the film. The carrier concentration of Li-ZnOdecrease with growth temperature and anealling temperature increasing, which becauseof Lizn-Lii donor compound is converted to Lizn acceptor in high temperature. Hightemperature will affect atomic orbital hybridization and defect, so photoluminescenceintensity of Li-ZnO thin film decreases with annealing temperature and growthtemperature increases.Studies show that argon oxygen ratio of10:1, the Li-doped ZnO thin films has thebest crystallinity. With the oxygen content increases, band gap of Li-doped ZnO thin filmbecomes gradually smaller. When the argon oxygen ratio is10:1, Li-doped ZnO thin filmhas the highest concentration of carriers. This shows argon oxygen ratio of10:1, theacceptor level can be reduced to maximize the formation of donor levels...