Temperature Studies of Zinc Tin Oxide Photoluminescence for Optical O₂ Sensing

The photoluminescence of zinc tin oxide (ZTO) is investigated regarding its temperature (room temperature to 433 K) and gas-phase oxygen (O₂) concentration (250 ppm to 20 vol %) dependence. Both the emission intensity and electrical conductance decrease upon O₂ adsorption, as ZTO is an n-type semiconductor. A temperature increase significantly quenches the photoluminescence intensity and results in a strong blue-shift of the orange and red emission. The temperature-induced exponential intensity decay can be described with an empirical equation similar to the Fermi–Dirac statistic. The obtained activation energies allow to propose a detailed band scheme of ZTO.