Journal of Crystal Growth, Vol.329, No.1, 12-19, 2011
Electron backscatter diffraction analysis of a CZT growth tip from a vertical gradient freeze furnace
Electron backscatter diffraction (EBSD) was used to characterize the growth-tip region of a 4.2-cm diameter CdZnTe (CZT) boule grown using low-pressure Bridgman method in a vertical gradient freeze furnace. The boule was sectioned and polished and a section taken along the boule longitudinal centerline with an approximate surface area of 1-cm(2) was used for optical and scanning electron microscopy. A collage was assembled using EBSD/SEM images to show morphological features, e.g., twin structure, grain structure, and overall crystal growth direction. Severely twinned regions originating from the tip and side walls were observed. The overall growth orientation was close to < 1 1 0> and <1 1 2> directions. In some regions, the (0 0 1) poles of the CZT matrix aligned with the growth direction, while twins aligned such that (1 1 1) and (1 1 2) poles aligned with the growth direction. In some other areas, (1 1 2) or (0 1 1) poles of the CZT matrix aligned with the growth direction. New relationships between the CZT matrix and large Te polycrystalline particles were revealed: (1 1 (2) over bar)(CZT)parallel to(1 (1) over bar 0 0)(re) and (0 0 1)(CZT)parallel to{0 (1) over bar (1) over bar 1}(Te). (C) 2011 Published by Elsevier B.V.
Keywords:Crystal structure;Defects;Growth models;Gradient freeze technique;Cadmium compounds;Semiconducting ternary compounds