Polarity determination of CdTe crystals by electron diffraction

The polarity of cadmium telluride crystals has been determined by a novel electron diffraction technique. This technique employs an electron microscope in normal operating conditions, and is applicable to any noncentrosymmetric crystal, provided that the deviation from centrosymmetry is not too small. We have thus identified the best {111} face for epitaxy on CdTe as the (1̄1̄1̄)Te face. This is in agreement with recent x-ray results and Rutherford backscattering results. Chemical etching characteristics of {111} faces were used to compare our results with previous polarity determinations. One commonly used etch is found to be unreliable for polarity identification.