Microscopic Theory for Point-Defect Effects on Photon Absorption in Quantum-Well Systems

摘要

The effects of lattice point defects on the absorption of incident photons in a single-quantum-well system are investigated by using a quantum-statistical theory. Our self-consistent theoretical model includes the defect-induced vertex correction to an unscreened dynamical polarization function of doped electrons under the ladder approximation. Meanwhile, the intralayer dynamical screening to the Coulomb interaction between charged point defects and conduction electrons are also taken into account within the random-phase approximation. The numerical results for nonlinear variations in absorption spectra by defects are demonstrated and analyzed for various defect densities. The combination of the current theory with a space-weather forecast model will enable novel designs of satellite onboard electronic and optoelectronic devices with radiation-hardening protection and extended lifetimes. More specifically, this theory facilitates a better characterization of photodetectors not only for high quantum efficiency and low dark current density but also for radiation tolerance or mitigation of radiation damage.