Investigation of digital alloyed AlInSb metamorphic buffers Available to Purchase

Al_1-xIn_xSb metamorphic step-graded buffers with Al_0.6In_0.4Sb terminal layers, designed to serve as a virtual substrate to support integrated InAs_0.5Sb_0.5 long-wave infrared absorber layers, were grown on GaSb wafers via molecular beam epitaxy. Two different structural profiles were used to define the effective composition of each buffer step: one based on digital alloys (1 nm period, ∼1.6 unit cells) and the other based on short period superlattices (10 nm period, ∼16 unit cells). Characterization via optical Nomarski microscopy, x-ray diffraction reciprocal space mapping, and transmission electron microscopy indicates that the digital alloy based structure behaves similar to that expected for a conventional bulk ternary alloy based structure, while the short period superlattice structure exhibits significantly hindered relaxation within the buffer layers.