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

The pressure dependences of the absorption edges in single crystals of CuIn S2, 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, a nd 53 meV/GPa for CuTnS(2), CuInSe2, and CuInTe2, respectively. We found th at the pressure coefficient of the energy band gap changes significantly wi th anion atomic number and that the empirical rule for the pressure deforma tion potential suggested for zinc-blende compounds has to be modified for C uInVI2 chalcopyrite semiconductors.