Controlled n-type doping of antimonide/arsenide heterostructures using GaTe

The authors used stoichiometric GaTe in Riber 32P and 21T systems. After outgassing at 425/spl deg/C, they obtained higher-than-expected carrier concentrations: 10/sup 18//cm/sup 3/ at T/sub GaTe/=350/spl deg/C. Following additional outgassing at 500/spl deg/C, the carrier densities were at lower levels and reproducible. This is consistent with the evaporation of elemental Te or Ga/sub 2/Te/sub 3/ during the initial growth and outgassing. Similar densities were observed for GaAs, AlSb, and GaSb. The growth temperatures for the GaAs layers were 550-600/spl deg/C, compared to 500/spl deg/C and 450/spl deg/C for AlSb and GaSb, respectively. Undoped GaAs layers grown after the use of GaTe exhibited a p-type background of 10/sup 14//cm/sup 3/, indicating negligible Te contamination due to a memory effect.