ChemInform Abstract: Cu₃TaSe₄ and Cu₃NbSe₄: X‐Ray Diffraction, Differential Thermal Analysis, Optical Absorption and Raman Scattering.

Abstract

Cu 3TaSe4 and Cu3NbSe4: X-Ray Diffraction, Differential Thermal Analysis, Optical Absorption and Raman Scattering. -The title compounds are characterized by XRD, differential thermal analysis in the temperature range of 300-1500 K, optical absorption measurements, and Raman spectroscopy. Both compounds crystallize in the space group P43m. Cu3TaSe4 and Cu3NbSe4 melt incongruently at 1328 and 1206 K, respectively, and show several solid-to-solid transitions at lower temperatures. Cu 3TaSe4 exhibits an indirect band gap at 2.43 eV and Cu3NbSe4 an indirect gap at 2.14 eV and a direct gap at 2.45 eV. -(GRIMA-GALLARDO*, P.; SALAS, M.; CONTRERAS, O.; POWER, C.; QUINTERO, M.; CABRERA, H.; ZUMETA-DUBE, I.; RODRIGUEZ, A.; AITKEN, J.; BRAEMER-ESCAMILLA, W.; J. Alloys Compd. 658 (2016) 749-756, http://dx.

Sulvanites: The Promise at the Nanoscale

“…Of the available measurements, Cu 3 VS 4 has the smallest of the experimental band gaps at 1.3–1.55 eV [ 4 , 11 , 25 ], while Cu 3 TaS 4 has the largest at 2.70–2.83 [ 7 , 11 ]. The other experimental values are 2.50–2.60, 2.14–2.20, and 2.35–2.43 eV for Cu 3 NbS 4 [ 11 , 34 ], Cu 3 NbSe 4 [ 34 , 53 ], and Cu 3 TaSe 4 [ 7 , 10 , 53 ], respectively. From these measurements, the band gaps are seen to vary by enlarging the ionic radius of the chalcogen (transition metal) ion, as predicted by computational studies.…”