Improvement of the structural and electrical properties of InAsSb epilayer using Sb-rich InAsSb buffer layer grown by hot wall epitaxy

We have investigated the crystalline quality of InAsxSb1−x epilayers grown on Sb-rich InAsSb buffer layer and on GaAs (0 0 1) substrates by hot wall epitaxy (HWE). The epilayers are grown at different arsenic (As) temperatures of 250, 270 and 280 °C. X-ray diffraction results indicate that the arsenic composition (x) of the epilayer is increased with increasing As temperature. It is observed that the crystalline quality of the epilayers with x=0.2 and 0.6 has been improved by using the buffer layer. Scanning electron micrograph of the epilayer with As composition of x=0.2 shows a homogeneous surface morphology with respect to the epilayer directly grown on GaAs substrates. On the other hand, the quality and homogeneity of the epilayers having x=0.8 deteriorate despite the growth of the buffer layer due to relatively large lattice mismatch between the epilayer and GaAs substrate. Hall effect measurements of the samples (x=0.2 and 0.6) demonstrate an increase in the electron mobility of the layer while it is decreased for the samples with x=0.8.