Design and characterization of type-II superlattice-based InAs/AlSb/GaSb detector structure

In this study, N-Structured based InAs/AlSb/GaSb Type-II Superlattice pbin type detector structures are investigated. These systems make absorption in the infrared region in the electromagnetic spectrum as detectors. Structural characterization of these systems is aimed. n-type GaSb is used as the substrate. InAs/AlSb/GaSb-based repetitive SL layers are formed as n-layer, i-layer, p-layer, and p-contact layer from the bottom InAsSb layer to the top GaSb cap layer for 120, 300, 15, and 80 periods, respectively. Structural characterization of all layers is made by using SIMS and XRD systems analyses. The structural depth profile of the SL layers has been presented comparatively through SIMS analysis. The interfacial transitions observed in the depth profile are consistent with the designed T2SL layers. By using XRD characterization, crystal quality parameters, lattice constants, periodicity, and deviation of superlattice peak from the substrate are determined. Such dislocation density and strain are measured AS 7.85x107cm−2 and 6.4x10-3 nm, respectively. AFM analysis technic is used to examine the surface morphology of the structure. Also, SEM analysis is used to examine the cross-section of the structure. The cross-sectional measurements allowed the observation of interfacial transitions within the SL structure. In this study, super lattice with high crystal quality is achieved and results show that T2SL detector structures have succeeded.