The influence of a flow of low-temperature nitrogen plasma on the morphology, electric properties, and UV photoconductivity of ZnO films on sapphire

We have studied the influence of a flow of high-enthalpy nitrogen plasma generated by a dc plasmatron on the morphology, electrical properties, and UV photoconductivity of ZnO films on sapphire substrates. It was found that the resistance of nitrogen-plasma-treated ZnO films increased (by a maximum factor of 10$^4$) and the processed films exhibited clearly pronounced response to UV irradiation. The UV responsivity of current and the current pulse contrast at 6 V were on a level of 3.6 $\times$ 10$^{-5}$ A/W and 16, respectively. The photocurrent pulse rise and decay times were $\sim$0.45 s.