Theoretical and experimental studies on the improvement of the response of n-type III-V QWIPs to TE mode infrared radiation

From the theoretical calculations on bound-to-continuum transitions in III-V compound n-type square well QWIPs based on the eight band k.p model incorporated with the envelope function approximation, it was found that a small response to TE mode infrared field excitation is possible. The role of the interband transition momentum matrix element P=-ix|X> within different regions of the QWIP is investigated, using two different material systems, namely GaAs/AlGaAs and InGaAs/GaAs. An asymmetric step well QWIP based on the study has been designed to improve the response to TE polarized excitation. The experimental measurements on the responsivity of the asymmetric QWIP are also presented.