p-type arsenic doping of Hg1-xCdxTe by molecular beam epitaxy

Growth of in situ As doped Hg1-xCdxTe by molecular beam epitaxy and activation of As at 250 degrees C is reported. We have used elemental arsenic, As-4, as the p-type dopant source. The activation of As was observed in the 10(16)-10(18) cm(-3) range after a low temperature annealing step at 250 degrees C. However, for doping levels above 5 X 10(18) cm(-3), we have observed that the As activation efficiency drops. it is speculated at this time that self-compensation and formation of neutral As complexes may limit doping efficiency at very high levels. We also report our data on the structural and electrical characteristics of these As doped p-type layers using secondary ion mass spectroscopy analysis, and Hall effect measurements. An acceptor activation energy of 5:4 meV was obtained based on the dependence of the Hall coefficient on temperature. This Value was attributed to singly ionized As located on a Te site (As-Te(.)) acting as an acceptor. A brief discussion on activation mechanism of As doped p-type HgCdTe material is also presented. (C) 1997 American Institute of Physics. [S0003-6951(97)02845-3].