RHEED studies of the surface morphology of α-Sn pseudomorphically grown on InSb(100) by MBE-a new kind of non-polar/polar system

The surface morphology of alpha -Sn(100) films grown pseudomorphically by MBE on InSb(100)-(4*2) surfaces prepared by an improved substrate cleaning method is investigated by RHEED. The authors report two new reconstructions for the alpha -Sn(100) surface, p(2*2) and c(4*4), together with the formation of 1D disorder and atomic steps as the thickness of the overlayer approaches 0.2 mu m. These surface reconstructions are very similar to those of the Si(100) surfaces and structural models and energetics for the two surfaces are compared. The presence of atomic steps on the alpha -Sn surface opens up the possibility of growing defect-free non-polar superlattices based on narrow band gap semiconductors.