MBE growth of terahertz quantum cascade semiconductor lasers

We report here the growth, fabrication, and operation of two different quantum cascade laser structures that emit in a single cavity mode in the terahertz regime; Both laser designs employ a chirped superlattice active region in a QC structure, comprising seven GaAs quantum wells separated by Al/sub 0.15/Ga/sub 0.85/As barriers, with a novel type of waveguide that provides confinement of the very long wavelength radiation to a very thin, highly doped buried layer.