Our research program objectives are the design and growth of novel InAlGaN-based quantum-cascade lasers (QCLs) operating in the mid-infrared spectral region. The materials for these devices will be grown by metalorganic chemical vapor deposition and will be characterized by a variety of techniques, including X-ray diffraction, optical absorption, photoluminescence, and transmission electron microscopy. The QCL devices offer the potential for a dramatic performance improvement over other types of injection lasers including a smaller dependence of the threshold current upon operating temperature (i.e., a higher To), a more stable emission wavelength vs. temperature, and higher quantum efficiency. In addition, the III-N materials potentially offer significant advantages over other III-Vs used for infrared laser applications. This program will lead to the demonstration of nitride QCLs emitting in the near infrared (IR) in the 4-12m-wavelength regime used in optical sensing applications, as well as potentially at other longer-wavelength mid-IR wavelengths (e.g., 15-30m). Other possibilities include the realization of 1.33 and 1.55mm lasers using this approach. Graduate student training is emphasized in this program.
