Optical and electrical properties of SnSe2

Abstract

The optical constants n and κ of crystalline C6, n-type SnSe₂, at 290 and 77 °K, have been measured over the photon energy range 005-37 ev. An analysis of the absorption measurements indicates that the intrinsic SnSe₂ absorption edge (at 77 °K) arises from forbidden indirect transitions across energy gaps of less than or equal to 103 and 130 ev, and allowed direct transitions across an energy gap of 197 ev; the direct transitions give rise to an inflexion in the spectral distribution of 2, the imaginary part of the dielectric constant. The crystal birefringence Δ (at a wavelength of 1 μm) has been determined, and the electrical conductivity Eperpendicularc and lattice parameter a₀ measured over the temperature range 77-290 °K. The properties of SnSe₂ are compared with those of other isostructural IV-VI compounds.