Molecular beam epitaxial growth and characterization of 2-in.-diam Hg1−xCdxTe films on GaAs (100) substrates

Abstract

Hg1−xCdxTe films with 2 in. diameters have been grown by molecular beam epitaxy on GaAs (100) substrates. These films were grown in both the (100) and (∼(111)) B crystallographic orientations and in both conduction types. They were characterized by in situ electron diffraction, infrared absorption, and van der Pauw dc Hall measurements. Their surfaces were shiny and mirrorlike from center to edge. The Cd concentrations (x) of these films were very uniform, exhibiting standard deviations (Δx) as low as 0.7% of the mean (x̄). Their thicknesses also were uniform within 0.6%. These films were completely uniform in their conduction types; that is, the n-type films were entirely n type, and likewise for the p-type films. The Hall mobilities of these films show them to be of high quality, with values as high as 6.7×102 cm2 V−1 s−1 for the p-type (x=0.22) and 1.8×105 cm2 V−1 s−1 for the n-type films (x=0.21). These results represent an important achievement toward the future of infrared detector technology.