Dynamical screening effects on dark current in a quantum-well infrared photodetector

Dark currents are calculated in ${\mathrm{Al}}_{0.27}{\mathrm{Ga}}_{0.73}\mathrm{A}\mathrm{s}/\mathrm{G}\mathrm{a}\mathrm{A}\mathrm{s}$ heterojunction based quantum well taking the thermionic field emission current into account. In our model the currents are calculated by taking emission of electrons from the bound state inside the well to the continuum scattered by the coupled plasmon-phonon modes. The calculated dark currents are compared with those obtained taking the sum of thermionic field emission currents arising individually from plasmon- and phonon-scattering processes and experiments. Compared to previous theoretical results the present dark currents agree reasonably well with experiments due to the inclusion of dynamical screening processes.