Optical properties of polycrystalline AgxGa2−xSe2 (0.4⩽x⩽1.6) thin films

Polycrystalline thin films of AgxGa2−xSe2 (0.4⩽x⩽1.6) were prepared onto cleaned glass substrates by the stacked elemental layer (SEL) deposition technique. All the films were annealed in situ at 300 °C for 15 min. The compositions of the films were measured by energy-dispersive analysis of X-ray (EDAX) method. The structural and optical properties of the films were ascertained by X-ray diffraction (XRD) and UV–VIS–NIR spectrophotometry (photon wavelength ranging from 300 to 2500 nm), respectively. The influence of the composition on the optical properties of the material has been investigated. Microstructural perfection is quite evident from the abrupt descent around specific energy of photons in the transmittance spectra. Stoichiometric or slightly silver-deficient films show optimum electron transition energy and minimum sub-band gap absorption.