TEM and X-ray investigations of defect structure of PbSnTe crystal

The Pb_0.8Sn_0.2Te single crystal grown by the Bridgman technique was examined by X-ray and TEM methods. The X-ray reflection topography revealed that the PbSnTe crystal consisted of monocrystallinic blocks with linear dimensions of 1–5 mm separated by low angle boundaries of tilt-twist character. “As grown” defects observed by TEM method have been identified as single perfect dislocations and dislocation pairs. A mean density of dislocations inside the crystal blocks was no more than 10³ cm⁻². Except “as grown” defects rows of mobile dislocations were observed. All of dislocations lines were characterized by the same type of Burgers vector, i.e. b = 1/2a〈110〉.