OPTICAL-ABSORPTION COEFFICIENTS OF SEMICONDUCTOR QUANTUM-WELL INFRARED DETECTORS

The optical absorption coefficients of semiconductor quantum-well infrared detectors have been carefully analyzed in the most general way using quantum perturbation theory. We have calculated the optical transitions between discrete subbands in quantum-well systems and between continuous energy bands of bulk materials as well as mini-subbands formed in semiconductor superlattices. Nonparabolic effects in energy spectra and the effect of different doping concentrations have also been investigated. The optimal directions, the corresponding absorption coefficients, and the quantum-well widths as functions of responding radiation frequency ℏω are listed in a table for the four most commonly used materials AlAs, GaAlSb, Si, and Ge as a guide for device designs. © 1995 American Institute of Physics.