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.

Structural properties of chalcopyrite thin films studied by Raman spectroscopy

“…The intensity of a resonant Raman mode is influenced by the absorption edge and the electronic density of states near the edge. In this case, an otherwise weak phonon mode, like the E 1 mode at 277 cm -1 , can be more intensive than the A 1 mode at 187 cm -1 , which is usually the phonon mode with the highest intensity among all modes of the chalcopyrite crystal lattice [21,22,37,38].…”

“…The excitation wavelength is usually selected with respect to the following factors: 1) the reduction of elastically scattered light, 2) the higher absorption of light near the material band-gap [36], 3) the optical penetration depth [36], and 4) the spectral separation of the scattered light from the PL emission of the chalcopyrite. The Ar + -laser lines, 488.0 nm [17,25] and 514.5 nm [20,31], the Kr + -laser lines, 676.4 nm, and 647.1 nm [21,22], as well as the lines of continuously tuned lasers, such as the Ar + -laser pumped Ti:Sapphire-laser [37,38], have been used to excite Raman scattering on CuGaSe 2 . In case that the photon energy of the excitation laser beam approaches the energy of an electronic transition, a resonance is observed in the scattering intensity.…”

Solution growth of by the temperature difference method under controlled S vapor pressure

“…Especially, In-rich alloy including CuInS 2 is expected as a material for efficient solar cells. Many growth techniques have been reported to grow bulk CuInS 2 and CuGa 1Àx In x S 2 thus far; the traveling heater method [1][2][3], the sintering method [4], the gradient freeze technique [5], the sulfurization horizontal Bridgman method [6], and the hot-press method [7]. However, it is difficult to control the stoichiometry and to grow bulk crystals with high crystalline quality.…”

Synthesis of zincblende CuInS2 and Fe-substituted CuInS2 by the reaction of binary colloids

“…As compared to CIS, the bands at 307 and 340 cm −1 were antistoke shifted with reduced intensity. Also, the change in the location of the band at 297 cm −1 confirmed the change in vibration mode caused by the introduction of iron in the CIS lattice [31][32][33]. Band gap of CIFS from the UV-visible spectroscopy measurements Fig.…”

“…Other bands at 255 cm −1 , and 340 cm −1 were assigned to E 1 LO /B 1 2LO and E 3 LO modes, respectively. The band at 307 cm −1 appeared at the higher side of the CH A 1 mode and was attributed to the A 1 mode of CuAu structural arrangement usually observed in CIS preparations [31][32][33]. Closer examination of the spectrum revealed critical differences in the positions and intensities observed for ZB and WZ [26].…”