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In this study, we present the theoretical investigation of type-II InAs/GaSb superlattice p-i-n detector. Kronig-Penney and envelope function approximation is used to calculate band gap energy and superlattice minibands. Variational method is also used to calculate exciton binding energies. Our results show that carriers overlap increases at GaSb/InAs interface on the higher energy side while it decreases at InAs/GaSb interface on the lower energy side with increasing reverse bias due to shifting the hole wavefunction toward to the GaSb/InAs interface decisively. Binding energies increase with increasing electric field due to overall overlap of electron and hole wave functions at the both interfaces in contrast with type I superlattices. This predicts that optical absorption is enhanced with increasing electric field. © 2013 American Institute of Physics

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The operational degradation of surface layers due to a rolling contact process was simulated for Hadfield steel by a special testing rig. A specific limited state based on cumulative depletion of plasticity was achieved.Precise evaluation of the surface layer's mechanical parameters is necessary for a service life prediction. Very low depth of localized dislocation hardening process doesn ́t allow the standard mechanical testing. The comparative instrumented indentation tests using Vickers and cylindrical indenter were used for evaluation of defined stage of surface degradation process. The intensity and reach of deformation hardening are partially limiting for particular methodology. The yield stress of surface layers was estimated according to an analytical model of uniaxial vs. indentation plastic flow ratio.