Decoration of extended defects in GaSb by Al doping as evidenced by cathodoluminescence studies

The effect of aluminium on the defect structure of GaSb crystals, grown by the vertical Bridgman technique, has been investigated by cathodoluminescen ce (CL) in the scanning electron microscope. Crystals have been found to be highly homogeneous along the growth axis with the exception of the top end which showed Al accumulation. The CL results show decoration of extended d efects by Al but contrary to the case of other dopants Al has not been foun d to cause a significative reduction of native accepters. A CL band at abou t 850 meV appears to be related to the presence of aluminium. (C) 1998 Else vier Science Ltd. All rights reserved.