A novel photon-assisted molecular beam epitaxial technique, compositionally modulated structures, was developed in order to suppress twinning during molecular beam epitaxial (Cd,Hg)Te growth. Strain effects, introduced by thin CdTe layers, suppressed planar twinning as well as lowering the dislocation density. A compositionally modulated structure epilayer consisted of multiple repeats of a basic unit comprising a thick (50 to 150nm) layer of (Cd,Hg)Te and a thin (2 to 5nm) layer of CdTe. The compositionally modulated structure epilayer was then interdiffused in a sealed quartz ampoule at temperatures which were consistent with n-type (or p-type) annealing. Compositionally modulated structures were also successfully applied to the low defect density growth of (Cd,Hg)Te on slightly lattice-mismatched CdTe substrates. It was noted that CdTe substrates were cheaper, purer and more readily available than lattice-matched (Cd,Zn)Te substrates.

R.W.Yanka, K.A.Harris, L.M.Mohnkern, T.H.Myers: Journal of Crystal Growth, 1991, 111[1-4], 715-9