Low-temperature Raman studies of sulfur-rich TlIn(S1−xSex)2 single crystals

Raman spectra of TlIn(S1-xSex)2 (0 ≤ x ≤ 0.25) single crystals in the frequency range 16-400 cm−1 were studied at T  = 30 K in the Z(XX+XY)Z¯ configuration. The experimental Raman spectra of TlIn(S1-xSex)2 single crystals were analyzed by multi-peak simulation by Lorentzian contours, enabling the peak frequencies, halfwidths and intensities to be determined. Their compositional dependences were studied. Compositional behaviour of Raman features revealed in the spectral regions 40-85 cm−1 and 190-220 cm−1 is discussed in view of different number of isovalent S and Se atoms in structural groups corresponding to the general formula of In4S10-ySey.