LUMINESCENCE PROPERTIES OF TRANSITION-METAL-DOPED GASB

The luminescence properties of transition-metal (Cr, V, and Ru)-doped GaSb single crystals have been studied by a cathodoluminescence (CL) t echnique in a scanning electron microscope. Spatial segregation of imp urities along the longitudinal direction of the crystals grown by the Bridgman method has been investigated. These dopants suppress the nati ve acceptor concentration to varying extent. The behavior of Ru has be en found to be different from the behavior of V and Cr. In particular the complete disappearance of the 777 meV (band A) emission has been o bserved in GaSb:Ru with a low doping level. A peak at 767 meV is also seen in this sample which, to the best of our knowledge, has not been previously observed in GaSb. The CL results have been complemented by x-ray-microanalysis measurements to ascertain the effect of doping lev el on the luminescence properties.