Abstract
In this paper, the study of defects in InAs/GaSb type-II superlattices using high-resolution an x-ray diffraction method as well as scanning (SEM) and transmission (TEM) electron microscopy is presented. The investigated superlattices had 200 (#SL200), 300 (#SL300), and 400 (#SL400) periods and were grown using molecular beam epitaxy. The growth conditions differed only in growth temperature, which was 370 °C for #SL400 and #SL200, and 390 °C for #SL300. A wings-like diffuse scattering was observed in reciprocal space maps of symmetrical (004) GaSb reflection. The micrometer-sized defect conglomerates comprised of stacking faults, and linear dislocations were revealed by the analysis of diffuse scattering intensity in combination with SEM and TEM imaging. The following defect-related parameters were obtained: (1) integrated diffuse scattering intensity of 0.1480 for #SL400, 0.1208 for #SL300, and 0.0882 for #SL200; (2) defect size: (2.5–3) μm × (2.5–3) μm –#SL400 and #SL200, (3.2–3.4) μm × (3.7–3.9) μm –#SL300; (3) defect diameter: ~1.84 μm –#SL400, ~2.45 μm –#SL300 and ~2.01 μm –#SL200; (4) defect density: 1.42 × 106 cm−2 –#SL400, 1.01 × 106 cm−2 –#SL300, 0.51 × 106 cm−2 –#SL200; (5) diameter of stacking faults: 0.14 μm and 0.13 μm for #SL400 and #SL200, 0.30 μm for #SL300.
Highlights
The presence of defects in semiconductor materials and epitaxial structures has a negative influence on their crystal quality as well as electrical and optical properties
The diffuse scattering was measured by reciprocal space mapping
It was shown that the values of integrated reciprocal space intensity and defect density calculated from scanning electron microscope (SEM) images increased with the number of periods in superlattices, regardless of the growth temperature
Summary
The presence of defects in semiconductor materials and epitaxial structures has a negative influence on their crystal quality as well as electrical and optical properties. The high-resolution x-ray diffraction (HRXRD) method is one of them and is successfully used for controlling the quality and structural parameters of InAs/GaSb superlattices, e.g., [16,17,23,24,25,26] In this case, the HRXRD characterization is usually based on the measurements and analysis of 2θ/ω scans, which do not give full information about the crystal quality of the superlattice. The HRXRD characterization is usually based on the measurements and analysis of 2θ/ω scans, which do not give full information about the crystal quality of the superlattice To resolve this issue a detailed analysis of measured reciprocal space maps (RSM) is required, which is an ideal tool for revealing and identification of defects. To the best of our knowledge, other defects (e.g., stacking faults) have not been investigated so far in this material system in this way
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
