J. Phys. IV France 7 (1997) C2-285-C2-286
X-Ray Spectroscopic Studies of some Compounds with the same Chemical Formula and Different Crystal StructureA.A. Lavrentyev1, I.Ya. Nikiforov2 and B.V. Gabrelian1
1 Department of Physics, Don State Technical University, Gagarin sq. 1, Rostov-on-Don 344010, Russia
2 Department of Physics, Don State Technical University, Gagarin sq. 1, Rostov-on-Don 344010 Russia
With the x-ray spectroscopy method two groups of semiconducting compounds are investigated. The first group consists of: CdIn2S4 (spinel type structure; F d 3 m – Ok7), CdGa2S4 and HgGaA ( the "defective" chalcopyrite; I 4- – S42). To the second group belong: Tl3TaS4 (that is made of coordinative tetrahedra [TaS4] and of structure units [TlS8]; I 4- 3 m – T43 ) and isostructural compounds Tl3TaS4 and TI3AsS4 (the structural type K3PS4; [formula: see text])- flnorescent K-emission bands and absorption K-spectra (XANES) of sulphur in compounds investigated are received with the resolution about 0.2 eV. The primary L2,3-emission bands of S have been studied using RSM-500 with resolution 0.4 eV. The electron energy structure of the valence bands are similar in isoelectronic compounds CdIn2S4, CdGa2S4 and HgGa2S4 that follows from the likeness of the forms of the x-ray emission bands in these compounds. At the same time the absorption SK-spectra (XANES) are alike only for CdGa2S4 and HgGa2S4 and differ significantly with SK-spectrum of CdIn2S4, that is due to the difference of S-atom sorroundings in these compounds. The similarity of the forms of all x-ray spectra in isostructural and isoelectronic compounds Tl3PS4 and Tl3AsS4 proves the likeness of the electron-energy structure in these compounds and of the environment of S-atom in these compounds. The emission and absorption spectra of S in Tl3TaS4 differ from ones of Tl3PS4 and Tl3AsS4, that is due to the fact, that Ta-atom is not isoelectronic to atoms of P and As, that results in the difference of S-atom surroundings and the electron-energy structure.
© EDP Sciences 1997