Effect of alloy disorder on photoluminescence in HgCdTe

Hg1-xCdxTe samples with x=0.38 and 0.57 fabricated by molecular beam epitaxy, both as-grown and after annealing, were studied. Photoluminescence (PL) was measured in the temperature range 4.2<T<300 K. The PL peak energy was found to be less than that of the energy gap by a certain value δE that depended on temperature. This effect was attributed to recombination of excitons localized at composition non-homogeneities. An analysis was carried out that provided a way for evaluation of a non-homogeneity measure. The amplitude of the non-homogeneities was shown to decrease by about 50% as a result of post-growth annealing in a He atmosphere and Hg vapour. (Abstract Copyright [2009], Wiley Periodicals, Inc.)