STUDIES ON STRUCTURAL AND ELECTROOPTICAL PROPERTIES OF MOVPE-GROWN ZNMGSSE BY CATHODOLUMINESCENCE

MOVPE-grown Zn1-xMgxSySe1-y/ZnSe heterostructures were investigated by cathodoluminescence (CL) combined with secondary electron imaging and atomic force microscopy. Pyramid-like defects were observed on the su rfaces. The spatially resolved CL measurements show a red-shift of the Zn1-xMgxSySe1-y band-edge emission at pyramid-like defect positions. This effect indicates a local variation of the chemical composition or the crystalline structure which leads to a variation of the band gap of Zn1-xMgxSySe1-y layers. The amount of the red-shift is not distinct ly correlated to the defect density and lateral size. (C) 1998 Elsevie r Science B.V. All rights reserved.