Highly strained InGaAsP films with high critical thicknesses

Elastically strained InGaAsP films with band gaps from 1.4 to 1.8 eV were grown on GaAs(111)B substrates by liquid phase epitaxy. For elastic strains up to 1% the critical thicknesses of the films substantially exceeded the predictions of the energy equilibrium theory by Matthews and Blakeslee. Among the various stress-relieving mechanisms proposed in the literature a stress-induced surface roughening has been found to be most relevant in our case.