Fig. 1. Surface topography of the swallow-tailed defect （a） optical microscope images with 200 magnification, （b） optical microscope images with 1000 magnification, （c） SEM image ,Note（s）: The arrays in （b） show different direction of raised side in triangle defect. The four dash lines in （c） are outlines of the defect. Capital A, B, C in （c） represent three EDS test areas.

Fig. 2. White light interferometry images of HgCdTe surface （a） 100 μm×100 μm area，（b） defect marked in figure （a），（c） triangular defects.

Fig. 3. Cross-sectional SEM images at different positions, the cross-sectional plane is (11¯1¯) face （a） schematic of outlines of swallow-tailed defect and cleavage positions A, B, and C, （b） shows position A after FIB etching, （c-e） represents position A, B and C after cleavage, respectively.

Fig. 4. Structure of swallow-tailed defect in epi-layer （a） Schematic graph, （b） defect structure from Diamond software.

Fig. 5. HRXRD omega-2theta scan pattern, （a） HgCdTe with swallow-tailed defect, （b） single crystal HgCdTe, （c） CdTe buffer of HgCdTe with swallow-tailed defect, （d） CdTe buffer of single crystal HgCdTe

Fig. 6. Schematic of different atomic sequence along [111] direction of （211） and （552） grain.

Fig. 7. Bright field microscopy images of CdTe after Everson etching （a）the typical triangle etch pits observed on type-I CdTe, （b）surface turned to black and no etch pit found in Type-II CdTe

Fig. 8. Bright field microscopy images of Te-terminated CdTe and Cd-terminated CdTe （a） Te-terminated CdTe，（b）Cd-terminated CdTe

Fig. 9. HRXRD ω-2θ scan pattern （a） 2 μm HgCdTe on CdTe/Ge, （b） 2 μm CdTe on Ge