Band edge tunability of M-structure for heterojunction design in Sb based type II superlattice photodiodes

We present theoretically and experimentally the effect of the band discontinuity in type II misaligned InAs∕GaSb superlattice heterodiodes. Calculations using the empirical tight binding method have shown the great flexibility in tuning the energy levels of the band edge in M-structure superlattice as compared to the standard InAs∕GaSb superlattice. Through the experimental realization of several p-π-M-n photodiodes, the band discontinuity alignment between the standard binary-binary superlattice and the M-structured superlattice was investigated via optical characterization. The agreement between the theoretical predictions and the experimental measurement confirms the capability of controlling the M-structure band edges and suggests a way to exploit this advantage for the realization of heterostructures containing an M-structured superlattice without bias dependent operation.