General trends in changing epilayer strains through the application of hydrostatic pressure.

Abstract

It is shown that the magnitude of in-plane strains decreases with applied hydrostatic pressure for several general classes of lattice-mismatched heterostructures, thereby making the structures more stable. In particular, the mismatch strain in strained-layer systems composed only of semiconductors from the same series, such as II-VI, III-V, or group-IV semiconductors, will generally decrease with the initial application of hydrostatic pressure, but will never vanish at any pressure. Strain-free conditions under pressure are only possible in heterostructures composed of semiconductors from different series, and then only when a phase transition does not occur first. The importance of using the exact form of Murnaghan's equation, rather than a linear approximation, in analyzing strains is also demonstrated.