Optical parameters of In-Se and In-Se-Te thin amorphous films prepared by pulsed laser deposition

The thin films of materials based on In-Se are under study for their applicability in photovoltaic devices, solid-state batteries and phase-change memories. The amorphous thin films of In2Se3-xTex (x = 0-1.5) and InSe were prepared by pulsed laser deposition method (PLD) using a KrF excimer laser beam (lambda = 248 nm, 0.5 J cm(-2)) from polycrystalline bulk targets. The compositions of films verified by energy-dispersive X-ray analysis (EDX) were close to the compositions of targets. The surfaces of PLD films containing small amount of droplets were viewed by optical and scanning electron microscopy (SEM). The optical properties (transmittance and reflectance spectra, spectral dependence of index of refraction, optical gap, single-oscillator energy, dispersion energy, dielectric constant) of the films were determined. The values of index of refraction increased with increasing substitution of Te for Se in In2Se3 films, the values of the optical gap decreased with increasing substitution of Te for Se in In2Se3 films. (C) 2007 Published by Elsevier Ltd.