High-quality highly mismatched InSb films grown on GaAs substrate via thick AlSb and InxAl1−xSb step-graded buffers

We investigated double-buffer structure which could enable us to grow a high-quality InSb active structure on GaAs (0 0 1). With thick AlSb and InAlSb step-graded buffer layers, we succeeded to obtain InSb films of very high mobility at room temperature. Using transmission electron microscopy, we confirmed attenuation of threading dislocations by the buffer layer. Surface roughness and its power spectral density were analyzed by atomic force microscopy. Furthermore, strain relaxation and mosaicity were investigated by high-resolution X-ray diffraction measurements.