CHARACTERIZATION OF SPATIAL HETEROGENIETIES IN DETECTOR GRADE CdZnTe

Synthetic Cd1-xZnxTe or 'CZT' crystals are highly suitable for the room temperature-based spectroscopy of gamma radiation. Structural/morphological heterogeneities within CZT, such as secondary phases that are thought to consist of Te metal and have detrimental impacts on detector performance. In this study, we used electron and X-ray-based imaging techniques to examine heterogeneous properties of detector grade CZT. Using experimental analytical techniques rather than arbitrary theoretical definitions, our study identifies two dominant secondary phase morphologies. The first consists of numerous empty, 20 (micro) m wide, pyramidal bodies (tetrahedra) or 'negative' crystals with trace quantities of particulate residue that exist as 65 nm sized particles containing Si, Cd, Zn, and Te. The other consists of 20 (micro)m hexagonal-shaped bodies, which are composites of metallic Te layers that contain a teardrop-shaped core of amorphous and polycrystalline CdZnTe which finally surrounds an irregular-shaped void