Optical Properties and Lattice Dynamics of Pure and S‐Alloyed Cu–Zn–Sn–Te Semiconductors: First‐Principles Calculations and Raman Scattering. Issue 6 (7th March 2022)

• Record Type: Journal Article
• Authors: Litvinchuk, Alexander P.; Dzhagan, Volodymyr; Mazur, Nazar; Yukhymchuk, Volodymyr O.; Kapush, Olga A.; Zahn, Dietrich R.T.
• Is Part Of: Physica status solidi. Volume 259:Issue 6(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-07
• Subjects: Cu2ZnSnTe4 -- DFT -- nanocrystals -- phonons -- Raman spectroscopy; Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.202100618
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract : The electronic band structure, the optical properties, and the lattice dynamics of the quaternary Cu2 ZnSnTe4 (CZTTe) semiconductor with kesterite crystallographic structure are calculated within first principles. The analysis of the phonon partial density of states shows that the highest frequency phonon mode involves mostly heavy Sn and Te atoms due to their exceptionally strong bonding. Experimental Raman spectra of Cu–Zn–Sn–Te nanocrystals, prepared by an aqueous colloidal synthesis, reveal a single characteristic line and its higher order overtones due to specific resonant conditions. In the case of Cu–Zn–Sn–(Te–S) alloy nanoparticles, other Raman features, related to Sn–S vibrations, appear in the spectra indicating a two‐mode type of transformation of their vibrational spectra. The effect of sulfur incorporation on the Te‐related frequency is opposite to the effect observed for the Se‐related frequency in CZTSSe alloys. Abstract : First‐principles calculations and experimental spectroscopy reveal a stable NIR‐absorbing semiconductor phase of the Cu–Zn–Sn–Te compound analogous to the well‐known kesterite Cu2 ZnSnS4 and Cu2 ZnSnSe4 . Due to specific resonant scattering conditions, the Raman spectra of Cu–Zn–Sn–Te are, however, very different from the latter two counterparts. A two‐mode behavior of the phonon modes as a function of Cu–Zn–Sn–Te1− x S x composition is established.