Mismatch tuning by applied pressure in ZnSe epilayers: Possibility for mechanical buffering

The effect of applied hydrostatic pressure on mismatch-generated strain in semiconductor epilayers is measured for ZnSe films on [001]-oriented GaAs and calculated for several common systems. We observe that pseudomorphic behavior persists in a 775-{} ZnSe epilayer until at least 60 kbar. In agreement with theory, the biaxial strain changes from compressive to tensile at 21±{}2 kbar, where exact lattice matching occurs. Our work suggests a ``mechanical buffering'' method for enhancing coherent growth of thick mismatched heterostructures.