Role of the thickness on the electrical and optical performances of undoped polycrystalline zinc oxide films used as UV detectors

In this paper we present the effect of thickness on the electrical and optical properties of intrinsic/nondoped zinc oxide thin films deposited at room temperature by radio frequency magnetron sputtering, able to be used as a semiconductor material on electronic devices, like for example ozone gas sensors and ultraviolet detectors. These films are polycrystalline with a c-axis preferential orientation parallel to the substrate. The films present a resistivity that varies from 5.0 × 104 Ω cm to 1.0 × 109 Ω cm with an optical visible transmittance of 85%. The sensor response exceeds more than five orders of magnitude when exposed to UV light recovering to the initial state in the presence of ozone.