Electronic Band Structures and Optical Properties of Type-II Superlattice Photodetectors with Interfacial Effect
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH
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The electronic band structures and optical properties of type-II superlattice T2SL photodetectors in the mid-infrared IR range are investigated. We formulate a rigorous band structure model using the 8-band k p method to include the conduction and valence band mixing. After solving the 8 x 8 Hamiltonian and deriving explicitly the new momentum matrix elements in terms of envelope functions, optical transition rates are obtained through the Fermi s golden rule under various doping and injection conditions. Optical measurements on T2SL photodetectors are compared with our model and show good agreement. Our modeling results of quantum structures connect directly to the device-level design and simulation. The predicted doping effect is readily applicable to the optimization of photodetectors. We further include interfacial IF layers to study the significance of their effect. Optical properties of T2SLs are expected to have a large tunable range by controlling the thickness and material composition of the IF layers. Our model provides an efficient tool for the designs of novel photodetectors.
- Theoretical Mathematics
- Atomic and Molecular Physics and Spectroscopy
- Quantum Theory and Relativity
- Solid State Physics