Resonant Raman scattering and luminescence in CuInS2 crystals

Abstract

Resonant Raman scattering and luminescence have been examined for CuInS2 crystals grown by the traveling heater method (THM) and the iodine vapor transport method (IT). Resonant Raman spectra of CuInS2 have been observed, and the spectra show seven single-phonon peaks and one two-phonon peak. Among them, three single-phonon modes have been found in the low-Raman-shift region because of resonant enhancement of phonon modes. The enhancement of these phonon modes is caused by incoming resonance mediated by bound excitons on the THM crystal, while it is attributed to outgoing resonance due to intermediate states of free excitons on the IT crystal.