Analysis of low doping limitation in molecular beam epitaxially grown HgCdTe(211)B epitaxial layers

Abstract

We report the results of the transport properties and the recombination mechanisms of indium-doped HgCdTe(211)B (x ≈ 23.0% ± 2.0%) layers grown by molecular beam epitaxy. We have investigated the origin(s) of the background doping limitation in these layers. Molecular beam epitaxially grown layers exhibit excellent Hall characteristics down to indium levels of 2 x 10¹⁵ cm⁻³. Electron mobilities ranging from (2-3) x 10⁵ cm²/v-s at 23K were obtained. Measured lifetime data fits very well with the intrinsic band-to-band recombinations. However, below 2 x 10¹⁵ cm⁻³ doping levels, mobility vs temperature curves starts to reflect nonuniformity in carrier distribution. Also, when we reduced the Hg vacancy concentration down to 10¹² cm⁻³ range, by annealing at 150°C, Hall characteristics shows an increase in the nonuniformity in the epilayers. It was found that after annealed at 150°C, the obtained SR defect level has a different origin than the previously obtain Hg-vacancy related defect level.