Physics and applications of Ge(x)Si1-x)Si strained layer heterostructures.

This article reviews recent advances in our current level of understanding of the physics underlying transport and optical properties of Ge(x)Si(1-x)/Si strained layer heterostructures. Included are discussions of critical (maximum) layer thicknesses, effects of coherency strain on the bandgaps of both Si and Ge(x)Si(1-x), and the influence of layer strains on the band alignments of Ge(x)Si(1-x)/Si strained heterostructures. Transport studies will center on the modulation doping results of both n and p-type heterostructures. Indeed these earlier transport studies provided essential information which led to an understanding of the band-alignment in these strained layer heterosturctures.