Origin of Defects in (111) HgTe Grown by Molecular Beam Epitaxy.

Films of HgTe grown in the (100) orientation by molecular beam epitaxy typically possess better electrical properties than do (111) films. Films with the latter orientation, when grown under conditions which lead to well-streaked RHEED patterns, still contain a columnar microstructure with a high density of twins and dislocations. Data taken by transmission electron microscopy and Auger sputter profiling suggest that these films suffer from island nucleation caused by adsorption of Hg onto the CdTe buffer layers. Comparisons are made with (111) samples grown with excess Hg flux and with (100) films, and prospects for improved (111) nucleation are discussed.