Development of intersubband (ISB) optoelectronic devices has greatly paralleled the progress made in III-V semiconductor epitaxy. Quantum cascade lasers (QCL) and quantum cascade detectors (QCD) are their own class of solid-state devices that span the mid-infrared (3-30 μm) and the THz region (60-300 μm). Together they cover the molecular fingerprint region where optical spectroscopy can measure and detect chemicals in solid, vapor, or liquid form. ISB devices allow great freedom in the choice of active region designs and materials selection. The growth and processing of a QCL or QCD requires new epitaxy techniques and the active region designs and the material systems employed are of continuing research. This makes ISB devices excellent tools for characterizing the growth, doping, interfaces, and the semiconductor alloys used in their fabrication.

The Optoelectronic Epitaxy group spezializes in these three research topics: