Crystal growth and qualitative properties evaluation of Cd_0.8Mn_0.2Te

Cd_0.8Mn_0.2 Te crystal ingot with size of φ30 mm × 120 mm was successfully produced with vertical Bridgman method. The crystalline structure was verified by X-ray diffraction to be a pure cubic zinc blende structure. Double-crystal rocking curve measurement showed the FWHM to be 47.2arcsec, indicating a high crystalline perfection. Chemical etching was applied to reveal the crystal defects, such dislocations, Te inclusions and twins. Adopting an optical microscope, scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), the morphology and distribution of these defects were analyzed. The results showed that the dislocation density was between 10⁵-10⁶ cm^-2. Twins was observed in the crystal with mainly the coherent twin. Te inclusions with the size of 1-5 μm distributed inhomogeneously in the crystal, and was more often observed at twin boundaries. The formation principles of these defects and methods to decrease them were further discussed.