Spectroscopic investigations of polycrystalline In_xSb_20−xAg₁₀Se₇₀ (0 ⩽ × ⩽ 15) multicomponent chalcogenides

The composition dependence of physical properties of chalcogenides has recently been studied for their phase change properties and energy conversion. In the present work, we report the structure, composition, optical and Raman spectroscopy results for bulk polycrystalline In_xSb_20−xAg₁₀Se₇₀ (0 ⩽ × ⩽ 15) samples. The phase quantification and composition have been studied by using XRD and EDX techniques. The alloy composition up to 5 at.% of indium resulted in crystallization of AgSbSe₂, while further increase in In content favored the formation of another chalcopyrite AgInSe₂ phase yielding the solid solutions for this alloy system. A decrease in band gap up to x = 5 followed by its increase with an increase in indium concentration has been observed. The variations in shape and position of characteristic Raman bands has been used for understanding the structural modifications of the network with the variation in indium content.