Raman and infrared spectra of CdIn2S4 and ZnIn2S4

Four one-phonon Raman lines have been found in CdIn2S4 (ZnIn2S4) spinels at 92 (72) cm-1, 186 (184) cm-1, 246 (253) cm-1, and 367 (372) cm-1 for incident photon energies well below the energy gap EG ∼ 2.4 (2.2) eV at 300 K. For photon energies close to EG, the 367 cm-1 mode underwent a resonant enhancement in CdIn2S4 and four infrared active but Raman forbidden F1u modes appeared in the CdIn2S4 and ZnIn2S4 Raman spectra: TO modes at 226 (221) cm-1 and 309 (312) cm-1, and LO modes at 274 (272) cm-1 and 340 (342) cm-1.