Pressure Dependence of Impurity Levels in CuGa(SxSe1-x)2 Alloys.

The effects of hydrostatic pressure on the binding energies of shallow acceptors in CuGa(SxSe_1-x)₂ are presented and discussed. The energy E_A decreases with pressure at a rate of -4.6 x 10^-4 eV GPa^-1 for x=1 and 9.2 x 10^-4 eV GPa^-1 for x=0.5. These results can be understood in terms of effective-mass theory because shallow levels are dominated by long-range forces which are much less sensitive to the interatomic separation (pressure).