The energy bands of SnS2 and SnSe2 are calculated using the local empirical pseudopotential method. The form factors of the pseudopotential were adjusted in such a way that the calculations reproduce the experimental values of the fundamental gaps. The space group D of these compounds is studied in detail and a comparison is made between the recent calculation by Fong and Cohen and the present work. Prom the pseudo wavefunctions the charge distributions of electrons and holes are calculated.



Die Bandstruktur von SnS2und SnSe2wurdemitderempirischen Pseudopotentialmethode berechnet. Die Potential-Formfaktoren wurden an experimentelle Daten angepast. Eine gruppentheoretische Analyse der Raumgruppe D wurde im Detail durchgefuhrt und mit den Ergebnissen von Fong und Cohen verglichen. Die Pseudowellenfunktionen. dienten zur Berechnung der Dichteverteilungen von Lochern und Elektronen.

The electronic structure of sns2 and snse2

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Wavelength Modulation Spectra and Electronic Band Structure of SnS2 and SnSe2

Single‐crystal platelets of n‐type SnSe2 have been grown by the vapor phase transport technique without using a transport agent. Optical absorption has been studied at 25 °C for light polarized perpendicular to the crystallographic axis of symmetry. Order numbers of interference fringes in the transmission spectrum have been uniquely assigned. Variation of refractive index and absorption coefficeint with energy has been reported. It is found that the intrinsic SnSe2 absorption edge arises from forbidden indirect transitions across an energy gap of 0.98 eV and allowed direct transitions across an energy gap of 2.1 eV.

Optical absorption spectrum of tin diselenide single crystals

Kramers-Kronig analysis was applied to the reflectivity of SnSe2 and SnS2 at room temperature, with E normal to the crystal c axis. Optical functions (joint density of states, effective number of electrons, energy-loss function and dielectric constants) were obtained between 0 and 40 eV and interpreted according to the electronic structure of the two compounds.

V. I. Donetskich

Papers

Energy band structure of SnSe2 crystals