HgTe–CdTe superlattices and Hg1−xCdxTe grown by low-temperature metalorganic chemical vapor deposition

Abstract

Listen

Translate article

We report low-temperature metalorganic chemical deposition of Hg1−xCdxTe and HgTe–CdTe superlattices using a thermal precracking technique. The success of the precracking technique depends on decomposing the incoming metalorganic reactants at a high temperature while allowing the epitaxial growth to occur at a lower temperature. The precracking technique enables one to grow Hg1−xCdxTe and HgTe–CdTe superlattices at temperatures of 200 to 250 °C. The Hg1−xCdxTe epilayers show infrared transmission with sharp cutoffs. The as-grown Hg0.7Cd0.3Te is n type and has a room-temperature mobility of 12 200 cm2/V s with carrier concentration of 2.7×1017 cm−3 and 77 K mobility of 27 000 cm2/V s with carrier concentration of 1.0×1017 cm−3. For the HgTe–CdTe superlattices, HgTe layer thicknesses as small as 60 Å were obtained. All the samples examined using transmission electron microscopy had sharp HgTe–CdTe interfaces. The HgTe–CdTe superlattice structures also exhibited sharp infrared transmission cutoffs. In addition, compared to the band gap of Hg1−xCdxTe alloy with the same composition, a narrowing of the superlattice band gap was observed as predicted by theoretical studies.