Buffer influence on AlSb/InAs/AlSb quantum wells

Buffer influence on AlSb/InAs/AlSb quantum wells (QWs) was investigated by using Hall measurement, atomic force microscopy (AFM) and X-ray diffraction (XRD). We found that the electron mobility of AlSb/InAs/AlSb QW with GaSb buffer is higher than that with AlSb buffer though the surface and crystal qualities of AlSb buffer are better than GaSb buffer. Relaxation measurement indicated that the 150 Å InAs grown on AlSb buffer is partially relaxed, while it is fully strained when grown on GaSb buffer, which is also supported by critical thickness calculation. Because of InAs relaxation on AlSb buffer, mismatch dislocations will appear in the InAs layer and the interfaces of InAs QW will get rough, which is suggested as the reason leading to the lower mobility of InAs QW grown on AlSb buffer than on GaSb buffer.