Optical properties and average flow of energy in AgInSbTe films used for phase change optical recording

Optical constants of amorphous (AgSbTe)(x)(In1-ySby)(1-x) films (AIST) for a typical composition (x = 0.4 and y = 0.7) deposited by the thermal evaporation technique, are calculated from transmittance spectra. They are also been calculated during the crystallization process induced by 1-h thermal annealing at different temperatures. The effect of heat treatment on the absorption coefficient, the extinction coefficient, and the refractive index of the films are studied. The optical gap for as deposited amorphous films is found to lie in near-IR region. The bandgap shifts resulting from annealing are also calculated for the crystalline films. Further, these results are used for a multilayer structure for AIST as the recording layer, illuminated by a laser beam. The flow of optical energy in the absorptive layers and hence the diffusion of the resultant heat throughout the structure are studied. (C) 2003 Society of Photo-Optical Instrumentation Engineers.