Eight-Band k.p Calculations of the Electronic States in InAs/GaSb Superlattices

In this paper, we present the absorption edge of (InAs)(6ML)/(GaSb)(n) superlattices, which has been determined with the use of the 8-band k.p method. The aim of the work was to develop a numerical tool, which gives the possibility to design InAs/GaSb superlattices for infrared detector structures. Most of works, which were published in this field till now, present the results of electronic states calculations performed with the use of the Empirical Pseudopotential Method (EPM) or Envelope Function Approximation (EFA) method. In this work we report on the results of simulations performed with the use of the 8-band k.p method, in which we have considered strain in a superlattice structure and the effects of heavy and light holes interaction at the interfaces in a superlattice. Calculations have been performed for the structures with asymmetric interfaces (i.e., InSb and GaAs ones). Superlattices grown on GaSb substrates were considered and a temperature of 0K was assumed. Results of simulations are in a good agreement with the results of PL spectra and absorbance measurements, which are presented in the literature. They are also in a good agreement with the results of simulations performed with the use of EPM and EFA methods.