STRUCTURAL INVESTIGATIONS OF POLYTYPES IN ZN1-XMGXSE BY TRANSMISSION ELECTRON-MICROSCOPY AND CATHODOLUMINESCENCE

Zn1-xMgxSe is of great interest with respect to applications in semico nductor optics as a buffer material for heteroepitaxy as well as for u se as an active light emitting component. Structural investigations ha ve been performed using transmission electron microscopy (TEM) and X-r ay diffraction (XRD). Luminescence properties have been characterized using photoluminescence as well as cathodoluminescence. The material s hows a transition from sphalerite to wurtzite structure with increasin g x. Within the transition range, near x = 0.19, regular and irregular sequences of hexagonal and cubic stacking grow. Regular sequences for m the polytypes 4H and 8H. The luminescence of the various crystal str uctures is found to be different. We used this effect to distinguish t he phases by spatially and spectrally resolved cathodoluminescence mea surements. (C) 1998 Elsevier Science B.V. All rights reserved.