Stability problems in CdTe/InSb heterointerfaces grown by temperature gradient vapor transport deposition at low temperature

Stability problems of the CdTe epitaxial layers grown on p-InSb (111) substrates at relatively low (∼ 180°) temperature were investigated. From the X-ray diffraction measurements, the grown layer was found to be a CdTe epitaxial film. Transmission electron microscopy (TEM) showed that the CdTe/InSb structures measured immediately after the growth at 180°C had good heterointerfaces. Photoluminescence measurements at 15 K for the as-grown CdTe/InSb heterostructures showed that the ratio of the peak intensity of the defect related emission to excitons bound to neutral donors was small. The high-resolution TEM measurements for the CdTe/InSb heterostructures held during three years showed that an U shaped domain appeared at the CdTe/InSb heterointerface and that the CdTe epitaxial layer near the interface changed to the CdTe polycrystalline or amorphous layers. These results indicated that the CdTe films grown on InSb substrates at 180°C should remove a significant stability problem due to interdiffusion at heterointerfaces for applications.