Trends in band-gap pressure coefficients in CuInVI2 (VI = S, Se, Te)

Abstract

The pressure dependences of the absorption edges in single crystals of CuInS2, CuInSe2, and CuInTe2 are studied at room temperature in this work. The linear pressure coefficients of the band gaps are 23 meV/GPa, 29 meV/GPa, and 53 meV/GPa for CuTnS(2), CuInSe2, and CuInTe2, respectively. We found that the pressure coefficient of the energy band gap changes significantly with anion atomic number and that the empirical rule for the pressure deformation potential suggested for zinc-blende compounds has to be modified for CuInVI2 chalcopyrite semiconductors.