Reduction of the dislocation density in molecular beam epitaxial CdTe(2 1 1)B on Ge(2 1 1)

The high dislocation density (2×107/cm2 for a thickness of 7 μm) in CdTe(2 1 1)B on Ge(2 1 1) has become a roadblock for the technological exploitation of this material. We present a systematic study of in situ and post-growth annealing cycles aimed at reducing it. An etch pit density of 2×106/cm2 was achieved by optimizing the growth conditions and annealing the samples in situ. This finding was corroborated by high-resolution X-ray diffraction, atomic force microscopy, photoluminescence and ellipsometry measurements.