Abstract

We report ensemble Monte Carlo (MC) particle modeling of nonequilibrium phenomena in multiple quantum well (MQW) structures associated with their excitation by infrared radiation. It is assumed that QWs are uncoupled, so that the vertical transport of electrons is due to their propagation in continuum states above the inter-well barriers. Such MQW structures are used in QW infrared photodetectors. The response of MQW structures to step-like pulses of high power infrared radiation at constant bias voltage and to step-like pulses of applied voltage at constant intensity of radiation is studied. Evolving our recent results [1,2], we show that stable periodic or near periodic electric-field domains and prolonged chaotic spatio-temporal pulsations of the electric field can occur in the MQW structures under consideration. The spatio-temporal variations of the electric-field distributions are accompanied with pronounced pulsing of the photocurrent. We consider n-type Al_{0 22}Ga_{0 78}As/GaAs MQW structures with different numbers of identical doped QWs separated by relatively thick wide-gap undoped layers The structural parameters and the ranges of average electric field (E = 10 − 20 kV/cm) and intensity of infrared radiation (I = 10²³ cm⁻²s⁻¹) correspond to the normal conditions in QW infrared photodetectors for heterodyne detection operation.

© 2000 IEEE