Anti-phase domain boundaries in ZnGeP2 (ZGP)

Coherently oriented cubic defects were recently reported to exist within th e tetragonal lattice of zinc-germanium-phosphide, ZnGeP2 (ZGP). X-ray diffr action utilizing whole pattern optimization (Rietveld method) and line-prof ile-fitting (LPF) enabled us to identify these defects. In the present rese arch, transmission electron microscopy (TEM) was used for direct observatio n of these defects. The bright field and dark field TEM images of the ZGP f oil indicate the existence of anti-phase domain boundaries (APB). Electron diffraction patterns clearly reveal two coherently oriented entities, one o f a tetragonal symmetry in accordance with the chalcopyrite lattice, the ot her however of a cubic symmetry. This confirms our former finding of the ex istence of coherently oriented cubic defects in as-grown chalcopyrite ZGP c rystal. (C) 2001 Elsevier Science B.V. All rights reserved.