Dynamic Conductivity of Electrons and Electron-Phonon Interaction in Open Three-Well Nanostructures.

The theoretical description of electronic tunneling transport through the three-well nanostructure (In0.53Ga0.47As/In0.52Al0.48As), being an expanded active region of quantum cascade detector, is presented. Using the solution of the Schrödinger equation, the dynamic conductivity caused by quantum transitions due to the interaction of electrons with electromagnetic field and phonons is calculated. Within the Green functions approach, the electron spectrum, renormalized due to the interaction with confined optical and interface phonons is obtained at cryogenic and room temperatures. The role of different mechanisms of electron-phonon interaction in the formation of temperature shifts, decay rates of electron states and electromagnetic field absorption bands is investigated. It is shown that independently of the temperature, the contribution produced by interface phonons into renormalized electron spectrum is several times bigger than that of confined phonons. However, the experimentally observed long-wave shift and broadening of absorption band at higher temperatures is, mainly, caused by the decreasing heights of resonant tunneling structure potential barriers. [ABSTRACT FROM AUTHOR]