Properties of C-doped LT-GaAs grown by MBE using CBr4

MBE grown LT-GaAs contains a high concentration of excess As which gives ri se to ultra-fast carrier-trapping time and excellent radiation hardness. Th ermal annealing can result in a dramatic decrease in Asc, concentration, ac companied by out-diffusion of excess As into adjacent layers. Doping the LT -GaAs layers with Be can thermally-stabilize Asc, antisite defects but Be i s known to be mobile at high temperatures. Carbon has been demonstrated as an attractive p-type dopant in GaAs, In this work, we report on a comparati ve study of the resistivity and carrier lifetimes of as-grown and annealed LT-GaAs:C and LT-GaAs:Be. (C) 1999 Elsevier Science B.V. All rights reserve d.