Rapid, nondestructive evaluation of macroscopic defects in crystalline materials: The laue topography of (Hg, Cd) Te

Abstract

Several (Hg, Cd) Te semiconductor alloys have properties which make them useful as solid state detectors. However, homogeneous alloy single crystal preparation requires unusual treatment. A two-step process is necessary because of the liquidus-solidus composition disparity at the melting point. Laue topography was found to be an efficient tool for optimizing parameters in an initial quench (to preserve homogeneity) and a subsequent solid state recrystallization (to promote large grain growth). Crystal perfection analysis using polychromatic X-ray diffraction is not an entirely new concept, but our initial interest led to a simplified Laue topography technique which is useful for rapid characterization of various macroscopic crystal defects. The utility of this method is demonstrated by a study of defects in bulk (Hg, Cd)Te crystals.