Absorption edge of Sn(Pb)2P2S(Se)e crystals under hydrostatic pressure

Abstract

The experimental studies of hydrostatic pressure effect upon fundamental optical absorption spectra in Sn(Pb)2P2S(Se)6 mixed crystals of different composition are carried out. The increase of Pb content in (PbySn1-y)2P2S6, (PbySn)2P2Se6 crystals is shown to result in the enhancement of electron-phonon interaction and to the reduction of the energy gap deformation potential Dg. Isomorphous substitution of S by Se in the Sn2P2(SxS1-x)6 solid solution row does not affect significantly the electron-phonon interaction value and Dg.