Analysis of High-Resolution X-Ray Diffraction for InAs/GaSb Superlattice

High-resolution X-ray diffraction is used to measure and analyze the InAs/GaSb superlattice grown on a GaSb (100) substrate using molecular beam epitaxy to obtain satellite peak number on the rocking curve, full width at half maximum (FWHM), peak intensity, and peak position. Then, the interface strain, mismatch, and InAs/GaSb superlattice period are calculated. In the experiment, the samples' surface morphology and surface roughness are tested and characterized using an atomic force microscope. The results show that the surface undulation and roughness of the InAs (10 ML)/GaSb(10 ML) superlattice with 50 periods are lower than other superlattice samples (such as the superlattice samples with short period or asymmetric structure). With an increase in the period, FWHM of the 1-order diffraction peak considerably decreases. Consequently, the surface morphology and continuity of the samples are improved. For the InAs (10 ML)/GaSb(10 ML) sample with 50 periods, the root-mean-square roughness is 0. 31 nm, more satellite peaks (+/- 4-order) can be observed in the rocking curve, FWHM of the 1-order diffraction peak is 0. 027 degrees, the periodic thickness is 5. 59 nm, and the average strain is 0. 43%.