Vibrational modes of AgIn3Te5 and effect of laser irradiation

Polycrystalline AgIn3Te5 has been synthesized by melt-quench technique. Phase homogeneity and crystal structure of AgIn3Te5 have been analyzed using X-ray diffraction (XRD). Vibrational modes and effect of laser irradiation on the surface of AgIn3Te5 have been studied by Raman spectroscopy. XRD analysis has shown that single phase AgIn3Te5 has crystallized in p-type tetragonal structure with P4¯2c space group. Raman spectrum of as-formed sample has shown a strong peak at 125.6 cm−1 which is attributed to A1 mode of chalcopyrite family and substantiates the results obtained from XRD analysis. Tentative mode assignment for the rest of the peaks observed has been done based on simplified Keating model and by comparison with modes reported as well as predicted theoretically for AgInTe2. Raman spectra obtained with laser beam power of 20 mW have revealed the formation of amorphous phase during acquisition. Interaction with 20 mW laser beam has resulted in the formation of In2O3 on the sample surface. The peak at 132.8 cm−1 that appeared after irradiation for 75 s may be attributed to In2O3 or to the silent A2 mode, which probably has become active due to defect formation.