Optical characterisation of single crystal 2H-SnS2 synthesised by the chemical vapour transport method at low temperatures

Abstract

Optical characterisation has been performed for single crystal 2H-SnS2 synthesised by the chemical vapour transport method at low temperatures. The optical absorption spectra measured in the normal-incidence geometry at room temperature show an indirect transition with an energy gap Eg=2.17+or-0.01 eV. Photoluminescence spectra at liquid helium temperature indicate two series of phonon replica of excitons with phonon energies LO1=62 meV and LO2=70 meV, where the zero phonon lines are 2.310 eV and 2.224 eV respectively.