Growth mechanisms of highly mismatched AlSb on a Si substrate

Abstract

We describe the growth mechanisms of highly mismatched (Δao∕ao=13%) defect-free AlSb on Si(001) substrates. Nucleation occurs during the first few monolayers of AlSb deposition by crystalline quantum dot formation. With continued growth, the islands coalesce into a bulk material with no vertically propagating defects. Strain energy from the AlSb∕Si interface is dissipated by crystallographic undulations in the zinc-blende lattice, as confirmed by high-resolution transmission electron microscopy (TEM) images. Reciprocal space analysis of the TEM images corroborates a crystallographic rotation associated with the undulations. The resulting AlSb material is >98% relaxed according to x-ray diffraction analysis.