Study on Te inclusions migration in CdZnTe single crystals during annealing under Cd/Zn vapor

The variation of density and diameter of Te inclusions in indium-doped Cd0.9Zn0.1Te(CZT)single crystals during annealing under Cd/Zn vapor were studied via IR microscopy observation.The results indicated that the density of Te inclusions distributed homogeneously before annealing,while after annealing,the density of Te inclusions increased for about one order near the surface,but decreased for one order inside,and the density increased gradually along the direction of temperature gradient.The diameter of Te inclusions was mainly between 1μm and 25μm before annealing,while those with the diameter45μm near the wafer's surface and those5μm and25μm inside increased notably after annealing.The reason for the above variation was determined by Te inclusions migration along the direction of temperature gradient.And during the migration,Te inclusions grew via incorporating with those with similar diameter and Ostwald ripening among those with comparatively different diameter.But the ripening was not sufficient so that many smaller Te inclusions remained in the annealed samples.