Determination and Analysis of Optical Constant of Annealed Sn2Sb2S5 Thin Films

The effects of annealing on structural, optical and electrical properties of Sn2Sb2S5 thin films were studied. Sn2Sb2S5 thin films were deposited on no-heated glass substrates by single source vacuum evaporation method. The as-deposited films were annealed in air for 1 h at 100, 200 and 300 degrees C. XRD study shows that annealed films are crystallized according to the preferential orientation (602). Optical measurements show that the thin films have relatively high absorption coefficients in the range of 10(5)-10(6) cm(-1) in the energy range of 2-3.25 eV. It is also found that Sn2Sb2S5 exhibit two optical direct transitions. The models of Wemple-DiDomenico and Spitzer Fan were applied for the analysis of the dispersion of the refractive index and the determination of the optical and dielectric constants. The electrical resistivity measurements are recorded, and two activation energy values are determined. The layers annealed at 200 and 300 degrees C exhibit a resistive hysteresis behavior. The properties reported here offer perspective to Sn2Sb2S5 for its application in many advanced technologies.