Lateral and depth inhomogeneities in Zn-based heterostructures grown on GaAs by MBE

The near-surface morphology, crystalline quality and contamination as well as depth and lateral homogeneity of background impurities and defects distr ibution in undoped ZnSe and ZnTe films grown by molecular beam epitaxy on G aAs(001) substrates were studied. The improvement of structural quality wit h the increase of film thickness was observed by X-ray diffraction and atom ic force microscope. But sufficient depth inhomogeneity of point and extend ed defect distribution is present in all films independently on their thick ness and increases after deposition of quantum wells. Transversal photovolt age measurements confirm the laminar inhomogeneity of investigated films. ( C) 2000 Elsevier Science S.A. All rights reserved.