Observation of Stacking Faults in Hexagonal CdS1−xSex Single Crystals by HRTEM and Their Influence on Cathodoluminescence (CL) Spectra

CdS1−xSex crystals of two different compositions (x=0.5 and 0.25) have been investigated by high resolution transmission electron microscopy and cathodoluminescence measurements. The first time, it could be established that inside the single CdS1−xSex crystals (hexagonal structure), many stacking faults exist which correlate to lamellae of cubic structure. Independent of their chemical composition intrinsic stacking faults of types I1 and I2 are the predominant defects in all the crystals examined. Moreover, a noticeable difference in the cathodoluminescence spectra could be observed for regions mainly having a hexagonal structure and from regions containing stacking faults.