Study of the optical properties of Sb2(Se1-xSx)3 (x = 0–1) solid solutions

This study presents a detailed analysis of the optical properties of the Sb₂(Se_1-xS_x)₃ (x = 0–1) polycrystals. Four antimony selenosulfide solid solutions Sb₂(Se_1-xS_x)₃ together with Sb2Se3 and Sb2S3 were synthesized from elemental precursors at the same synthesis conditions, only varying the x = S/(Se + S) value with a step of Δx = 0.2. Successful formation of the Sb₂(Se_1-xS_x)₃ solid solutions was determined by Raman spectroscopy and X-ray diffraction. As expected for the same type of crystal structure of Sb₂Se₃ and Sb₂S₃, the bimodal behavior of A_g Raman mode in Sb₂(Se_1-xS_x)₃ was detected. Temperature and excitation power dependent photoluminescence (PL) analysis of Sb₂(Se_1-xS_x)₃ was performed in order to look into the electronic and defect structure of these promising semiconductor materials for optoelectronic applications. The shift of the near band edge PL emission in Sb₂(Se_1-xS_x)₃ towards higher energies from 1.309 eV to 1.728 eV with increasing sulfur content was detected at T = 3 K. A change in the radiative recombination mechanism was detected being of excitonic origin in samples with x ≤ 0.2 and resulting from deep donor-deep acceptor pair recombination in samples with x > 0.2.