Crystal structure and vibrational properties of Cu₂ZnSiSe₄quaternary semiconductor

Abstract

The crystal structure of Cu2ZnSiSe4 semiconductor, grown by the chemical vapor transport method, was determined by the powder and single‐crystal X‐ray diffraction and shown to be orthorhombic wurtzstannite (space group P mn21). Lattice dynamics of Cu2ZnSiSe4 is studied by the low‐temperature off‐resonant polarized and resonant Raman scattering. Out of the total 45 optical vibrational modes allowed by the symmetry, 37 are observed in the spectra and are assigned to the specific lattice eigenmodes based on their polarization properties and a comparison of frequencies with the results of density functional lattice dynamics calculations. Good agreement between theoretical and experimental mode frequencies is established. The vibrational patterns for the most intense spectral lines in experimental spectra as well as pronounced resonant enhancement of Si‐related modes are discussed.

Raman Scattering Study of Mixed Quaternary AgxGaxGe1−xSe2 (0.167 ≤ x ≤ 0.333) Crystals

“…This type of vibrational mode transformation is typically observed for molecular crystals. Recently, however, extensive experimental and theoretical investigations of photovoltaic semiconducting materials such as Cu 2 Zn(Si,Ge,Sn)(S,Se) 4 and established assignment of observed lines to the particular lattice eigenmodes showed unambiguously that this is also applicable to the listed tetrahedrally coordinated semiconductors . As we will see further, our assumption on the two‐mode mode transformation in Ag x Ga x Ge 1− x Se 2 seems also to be valid.…”

Doping and alloying of kesterites

“…However, Cu 2 ZnSiSe 4 has the wurtzstannite structure [98,99] and there is a considerable size mismatch between Sn and Si [97]. Although first-principles calculations predicted miscibility in a wide compositional range [97], this could not be verified experimentally.…”

Raman characterization of Cu2ZnSnS4 nanocrystals: phonon confinement effect and formation of CuxS phases

“…19,20 Raman spectroscopy proved to be a very efficient diagnostic tool of the structure and composition of CZTS and related compounds. 7,9,[21][22][23][24][25][26][27][28][29] In many cases, it allows the CZTS polymorphs and secondary phases to be distinguished more reliably than by other conventional structural tools such as XRD, SAED, or TEM. The reasons for that are the better separation of phonon frequencies of the crystal structures in question as compared to their diffraction patterns, as well as the possibility to probe upon demand macro-, micro-, or even nanovolumes of the material.…”

“…The advantage of Raman spectroscopy becomes even more evident in the case of NCs, where additional signicant broadening of XRD reexes is contributed by NC size and size distribution. 30 Despite this, Raman studies of CZTS NCs prepared by colloidal chemistry are relatively rare up to now, 8,13,14 as compared to the intensively studied bulk CZTS crystals, thin CZTS lms 7,9,[21][22][23][24][25][26][27][28][29] as well as binary and ternary chalcogenide NCs. [31][32][33] Moreover, the reported results for CZTS NCs are contradictory to a certain extent.…”