Thermoluminescent response of Zn-modified titanium dioxide thin films subjected to continuous or pulsed ultraviolet radiation.

This work reports the thermoluminescent (TL) response of Zn-modified titanium dioxide thin films subjected to both continuous and pulsed ultraviolet (UV) radiation. The effect of varying Zn content on the film's compositional, structural, optical and thermoluminescent properties was investigated. Compositional characterization by X-ray photoelectron spectroscopy (XPS) showed that the atomic concentrations of titanium and oxygen correspond to stoichiometric TiO with Zn content from 0.3 to 2.6 at. %. Raman spectroscopy revealed a phase transition from rutile to anatase as the zinc content increases. Optical characterization showed important changes in the electronic structure of the films as Zn content increased; particularly, the band gap energy increased from 3.1 to 3.4 eV. The thermoluminescent response was studied using two UV irradiation sources: a continuous UV lamp emitting at 254 nm and a pulsed Nd:YAG laser with emission at the third harmonic (355 nm) with a pulse duration of 5 ns. The thermoluminescence glow curves exhibited one peak close to 190 °C. In general terms, for both irradiation sources linear relationships between TL response and irradiation time were observed. These results suggest that Zn-modified titanium dioxide thin films have potential applications in UV light detection and monitoring.