Reversible light-induced insulator-to-metal transition in yttrium oxyhydride epitaxial thin films

Abstract

Yttrium oxyhydride (YO_xH_y) exhibits unique photochromic properties in electrical resistivity and optical transparency, attracting photoelectronic applications such as smart windows and optical sensors. To enhance the photo-induced physical-property variation, in this study, we attempted 1): epitaxial growth of YO_xH_y thin films, and 2): irradiation of ultraviolet laser. Consequently, we achieved reversible change in resistivity by 7 orders of magnitude, in clear contrast to that previously reported in polycrystalline thin films using sunlight (one order of magnitude). Furthermore, we found that temperature dependence of resistivity was metallic after the irradiation of UV laser to the YO_xH_y thin film.