Raman Scattering Study of Mixed Quaternary Ag_xGa_xGe_1−xSe₂ (0.167 ≤ x ≤ 0.333) Crystals

Abstract

Experimental Raman scattering study of mixed AgxGaxGe1−xSe2 (0.167 ≤ x ≤ 0.333) single crystals is reported. The spectra transformation upon composition variation exhibits the two‐mode type of behavior, with lines of the end‐member compounds of the solid solution (AgGaSe2 and GeSe2) dominating in the spectra, whose relative intensities vary with composition.

Raman and Infrared Phonon Spectra of Novel Nonlinear Optical Materials PbGa2GeS6 and PbGa2GeSe6: Experiment and Theory

“…Later, we came to a similar conclusion while analyzing the phonon spectra of the stannite–kesterite type of quaternary materials of the type Cu 2 Zn(Ge,Si)(S,Se) 4 . Furthermore, an analogous property of the vibrational spectrum of quaternary chalcogenides was used recently in our qualitative interpretation of the Raman spectra of Ag x Ga x Ge 1− x Se 2 ( x = 0.333, 0.250, 0.200, 0.167) . An alternative notation of these crystals is AgGaGe n Se 2( n + 1) ( n = 2, 3, 4, 5 correspondingly), and they can be regarded as alloys of AgGaSe 2 and n × GeSe 2 .…”

“…To prove the assumption on the dominant role of (Ge,Ga)Se 4 tetrahedra in the formation of the phonon spectrum of PbGa 2 GeSe 6 , in Table , also shown are our recent experimental data for Ag x Ga x Ge 1‐ x Se 2 , as well as low‐temperature Raman results of Popovic and Jaksic for GeSe 2 . One can see a very good correlation of the frequencies from these works and many modes calculated for PbGa 2 GeSe 6 .…”

Phonon Raman spectroscopy of nanocrystalline multinary chalcogenides as a probe of complex lattice structures

“…Not only the position and width of the main Raman peak is sensitive to the crystals phase and stoichiometry, but also the intensity ratio of the less distinct features was shown to be a measure of particular point defects and defect complexes (figure 29) [44,212,213]. Importantly, only rarely reported are second-order Raman spectra of I-II-IV-VI NCs [177,214,215], although they could help a lot with the assignment of the questionable firstorder modes, particularly by applying excitations in resonant and off-resonant conditions, as demonstrated for several bulk counterparts [77,202,216].…”