ANALYSIS OF LOW DOPING LIMITATION IN MOLECULAR-BEAM EPITAXIALLY GROWNHGCDTE(211)B EPITAXIAL LAYERS

We report the results of the transport properties and the recombinatio n mecha nisms of indium-doped HgCdTe(211)B (x approximate to 23.0% +/- 2.0%) layers grown by molecular beam epitaxy. We have investigated th e origin(s) of the background doping limitation in these layers. Molec ular beam epitaxially grown layers exhibit excellent Hall characterist ics down to indium levels of 2 x 10(15) cm(-3) Electron mobilities ran ging from (2-3) x 10(5) cm(2)/v-s at 23K were obtained. Measured lifet ime data fits very well with the intrinsic band-to-band recombinations . However, below 2 x 10(15) cm(-3) doping levels, mobility vs temperat ure curves starts to reflect nonuniformity in carrier distribution. Al so, when we reduced the Hg vacancy concentration down to 10(12) cm(-3) range, by annealing at 150 degrees C, Hall characteristics shows an i ncrease in the nonuniformity in the epilayers. It was found that after annealed at 150 degrees C, the obtained SR defect level has a differe nt origin than the previously obtain Hg-vacancy related defect level.