Length mismatch in random semiconductor alloys. III. Crystalline and amorphous SiGe

In the third paper of this series on the length mismatch problem, we study binary semiconductor alloys in both their crystalline and amorphous forms. We have concentratred on SiGe alloys. Applying the theory developed in paper I, we obtain the mean length for both nearest and next-nearest neighbors as well as the nearest-neighbor length distribution for the crystalline alloy. We show that the theoretical results fall within the limits set by experiment. We check our analytical results against computer simulations. We examine the effect of amorphization on the internal strain, using the Wooten, Winer, and Weaire model, and find that the disorders due to the length mismatch and due to amorphization decouple.