MOLECULAR-BEAM EPITAXIAL-GROWTH OF (100) HG0.8CD0.2TEONCD0.96ZN0.04TE

The molecular beam epitaxial growth of (100) Hg0.8Cd0.2Te epilayers has been systematically investigated in order to optimize the growth parameters and in particular the Hg/Te flux ratio. Both the pyramidal hillock density and the mobility depend on the Hg/Te flux ratio. A minimum in the hillock density correlates well with the largest mobilities. As is well known, electrical properties are strongly influenced by structural defects. Structural defects due to non-stoichoimetry, i.e. vacancies and antisites, can be largly reduced by optimizing the Hg/Te flux ratio. It is shown that an optimum Hg/Te flux ratio exists within a narrow range between 270 and 360 at the growth temperature of 180-degrees-C, in contrast with the larger range of the Hg/Te flux ratio over which single-crystal growth could be maintained. The x values of the Hg1-xCdxTe epilayers were determined from the E0 gap dependence as well as from the E1 gap dependence. The difficulties encountered in determining the x value from normal transmission curves, i.e. from E0x, due to the Burstein-Moss shift are discussed.