Influence of Be doping placement in InAs/GaSb superlattice-based absorber on the performance of MWIR photodiodes

Doping of the absorption region is one of the most crucial aspects in the narrow-bandgap semiconductor design of a photodiode, especially if it is adjacent to the p-n junction area. It has a significant impact on various dark current mechanisms, and thus the overall performance of these devices. In this work, the influence of Be doping placement in the absorption region of type-II InAs/GaSb superlattice-based homojunction photodiodes on their performance was investigated. The analysis of diffusion, generation-recombination, shunt and the tunnelling components of the dark current was performed over a wide range of temperatures. Moreover, performance-limiting factors were considered as well as their impact on the most important figures of merit of the photodetectors. The photodiodes with Be-doped InAs layers in the absorption region achieved the best performance.