CARRIER THERMALIZATION BY PHONON ABSORPTION IN QUANTUM-WELL MODULATORS AND DETECTORS

In quantum-confined Stark effect based modulators and quantum-well det ectors, carriers are produced at the bandedge by optical absorption, I n most applications these carriers generate photocurrent and to do so these initially ''cold'' electrons must thermalize since the photocurr ent is dominated by over the barrier escapes of the carriers, The intr insic speed of the device is thus limited by this thermalization time. We carry out a Monte Carlo simulation to study the carrier heating by phonon absorption in quantum-well structures as a function of well si ze and barrier height, Carrier thermalization times are dominated by i ntrasubband polar optical phonon processes and typical times are 1-4 p s depending upon the well and barrier design.