X-ray diffraction study of GaSb/AlSb strained-layer-superlattices grown on miscut (100) substrates

摘要

Abstract: A series of superlattices were grown by molecular beam epitaxy on (100) GaSb substrates that had been miscut by 2, 3, and 4 degrees toward the $LS@011$GRT direction. These superlattices were then studied by scanning all possible $LB@444$RB or $LB@511$RB (asymmetric) reflections with high resolution multiple-crystal x-ray diffractometry. In addition, the (400) (quasi-symmetric) reflection was scanned. From peak splittings we extracted mismatch and tilt parameters for the epitaxial unit cell. We compared our results for the nontetragonal component of the distortion to calculations based on the coherent strain model of Hornstra and Bartels. We find that this model, which was developed for epitaxial growth on a general (hkl) plane, also describes our results for growth on vicinal (100) planes. The resolution of our data is sufficient to establish that the distortion was not purely tetragonal. A monoclinic unit cell symmetry adequately describes our results. !7