Highly reflective Er-doped ZnO thin-film coating for application in a UV optical ring resonator.

We achieved doping-induced optical variation in Erbium-doped ZnO (EZO) that may prove to be a promising material for use in optical ring resonators. EZO thin-film samples were deposited on n-type Si substrate via the sol-gel spin-coating technique followed by annealing in air at 500 °C. The doping-induced morphological variations of the deposited thin film were characterized using x-ray diffraction, ellipsometry, scanning electron microscopy and energy dispersive x-ray spectroscopy.