TWO-COLOR PHOTODETECTOR USING AN ASYMMETRIC QUANTUM WELL STRUCTURE

The past twenty years have seen an explosion in the realm of infrared detection technology fueled by improvements in III-V semiconductor technology and by new semiconductor growth methods. One of the fastest growing areas of this research involves the use of bandgap engineering in order to create artificial quantum wells for use in Quantum Well Infrared Photodetectors (QWIPs). QWIPs have an advantage over other infrared detectors such as Mercury Cadmium Telluride (MCT) because they have larger bandgaps and are therefore stronger and cheaper to manufacture. This thesis introduces one method of “multi-color” detection through the use of an asymmetric quantum well structure in which all energy transitions are possible. The QWIP structure in this thesis was designed to detect a laser wavelength of 1.06 ?m and a wavelength in the 8-10 ?m atmospheric window. The relevance of a detector that is tuned to these wavelengths is that it can be used on military aircraft as a laser spot tracker and an infrared imager providing much greater accuracy and dependability than older systems.