Type-II Superlattice Infrared Photodetector (T2SL IRPD) Miniband Modeling: An Atomistic NEGF Study
We theoretically investigate the physics of miniband formation in a T2SL Infrared Photodetector (IRPD) using an atomistic Green’s function formalism and also explore the criteria required for a viable design of the device at a specified regime of operation. For a fixed III–V material system like InAs/GaSb, we show that the operational wave-length and the photo-absorption primarily depend on the thickness of the constituting layers and the carrier effective masses. Separate spatial confinement of electrons and holes in different layers aids the control of photo-absorption by properly tuning the overlap of wavefunctions in subsequent layers. We have also explored the effects of lattice vibration scattering due to electron-phonon interaction on the transmission function and carrier density within the self-consistent Born’s Approximation using an incoherent self-consistent dephasing model. This study will offer deep insights on exploring the physics of minibands and will make the way for a better understanding of the transport properties.