TEM, chemical etching and FTIR characterization of ZnTe grown by physical vapor transport

ZnTe ingots were obtained by the physical transport method, using an in-house designed and built tubular furnace. The growth of ZnTe subsequently to the growth of a seed of this material allowed obtaining an ingot formed by only one large and single crystalline grain. TEM was used for the characterization of the as-grown ZnTe single crystal ingots and commercial single-crystalline wafers of the same material but grown by a higher temperature and more expensive technique, the Bridgman method. Both materials show very good crystalline microstructure, although some stacking faults were found in the commercial one. The infrared transmittance spectra of both materials were measured by FTIR and some differences, most likely due to differences in raw materials and growth methods, were found. The effectiveness and convenience of several chemical etchants to obtain the dislocation density and the minimal misorientation between adjacent subgrains in the as-grown ZnTe wafers were checked. It has been found as the most advantageous the chemical solution that does not produce over-etching. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)