Electrical activity, mode of incorporation and distribution coefficient of group V elements in Hg_1−xCd_xTe grown from tellurium rich liquid phase epitxial growth solutions

Abstract

Hg_1−xCd_xTe films were grown liquid phase epitaxially from tellurium rich solutions containing up to 10 at. % of the group V elements P, As, Sb, and Bi. Chemical analysis of the Te growth solutions and the films was carried out in conjunction with extensive Hall effect measurements on the films subsequent to various annealing treatments under Hg rich and Te rich conditions. Despite the presence of a large concentration of the group V elements in the Te source solution, the maximum concentration of these elements incorporated into the liquid phase epitaxially grown Hg_1-xCd_xTe appears to vary from <10¹⁵cm⁻³ for Bi up to 10¹⁷cm⁻³ for phosphorus and As implying a distribution coefficient varying from <10⁻⁵ for Bi up to 10⁻³ for P at growth temperature of ∼500° C. This low value of the distribution coefficient for group V elements for growths from Te rich solutions contrasts with the moderately high values reported in the literature to date for growth from Hg rich solutions as well as pseudobinary solutions (Bridgman growth). The widely differing distribution coefficients and hence the solubility of the group V elements for Hg rich and Te rich liquid phase epitaxial solutions is explained on the basis that the activity coefficient of the group V elements in Te rich solutions is probably orders of magnitude lower than it is in Hg rich solutions. Finally, the results of the anneals at 200° C under Hg saturated conditions with and without a 500° C Hg saturated preanneal have indicatedn top conversion in many of the films attesting to the amphoteric behavior of the group V elements in LPE grown Hg_1−xCd_xTe(s) similar to the previously reported behavior of P in bulk grown Hg_0.8Cd_0.2Te.