Work hardening and strain relaxation in strained-layer buffers

Fully relaxed buffer layers are of considerable importance for growth of high quality crystals on substrates having different lattice parameters. Recent experiments by Biefeld et al. [R. M. Biefeld, C. R. Hills, and S. R. Lee, J. Cryst. Growth (in press)] in the InAsSb system show that the degree of relaxation is considerably less than expected using conventional equilibrium models, but is more complete in continuously graded than in step-graded buffer layers. In the present letter, this observation is explained in terms of Taylor-type (dislocation interaction) work hardening.