Enhanced photoconductivity of ZnO films Co-doped with nitrogen and tellurium

Zinc oxide films are typically found to be n type, and conductive under most growth conditions and growth methods. Co-doping with multiple elements is one strategy for improving the electrical and optical properties of zinc oxide materials for optoelectronic device applications. Using pulsed-laser deposition, thin ZnO films were grown on c-axis oriented sapphire. The films were co-doped with nitrogen and tellurium. Depending on the relative concentrations of the dopants, the resistivity of the films was observed to increase by several orders of magnitude, significantly improving the photoconductive response. The enhancement of the photosensitivity reached a maximum at a tellurium concentration of around 1020cm−3.