PHOTOCHROMIC PROPERTIES OF YTTRIUM OXYHYDRIDE THIN FILMS: SURFACE VERSUS BULK EFFECT

Abstract Photochromic yttrium oxyhydride (YHO) films of different thicknesses but similar chemical composition were grown by reactive magnetron sputtering. Photochromic response of the films defined as the relative change in transmittance upon illumination increases almost linearly with thickness for films below 600 nm and saturates (≈ 50%) for thicker ones. These results suggest that the photochromic effect on YHO films has a bulk nature and might be limited by material transport on the microscale.