9410720 Gaylord Mid-infrared and far-infrared sources are needed for eye-safe wireless optical networks, remote sensing, medical treatment, and numerous other applications. This project investigates the modeling, fabrication, and testing of a new class of semiconductor optoelectronic sources directed at this need. These devices are based on quantum-mechanical electron-wave propagation effects. The quantitative analogies between electromagnetic propagation in dielectrics and ballistic electron transport in semiconductors, as developed with previous support, are being used to design nanostructure infrared emitters, detectors, and modulators. The optical transitions in these new devices use classically-free quasibound energy levels. In these energy states, an electron is free (unbound) classically. However, due to their quantum-mechanical wave nature, optical interference effects produce spatial confinement in Fabry-Perot type states. Using these quasibound states, the design, fabrication and testing of the first room-temperature semiconductor mid-infrared semiconductor laser is being attempted. Procedures are being developed that allow the energy positions and lifetimes of the quasibound states to be specified so that the wavelength of the laser can be chosen arbitrarily. In addition to optical methods for evaluating these devices, a series of independent measurements of electron transport through these nanostructures is being performed using the methods of ballistic electron emission microscopy/spectroscopy (a type of scanning tunneling microscopy). This allows separate independent testing of the electronic characteristics of the designed structures.
