Lattice Matched III-V Nitride Heterostructures

The III-V nitrides have recently emerged as the primary material system for UV/blue light emitters. Higher bandgap energy (Al,Ga)N alloys are currently employed as cladding layers for GaN and (In,Ga)N active region LEDs and laser structures. Lattice mismatch between the cladding and active regions, however, restricts both the thickness and composition of the layers which in turn limits the operating efficiency of the devices. This is particularly problematic for the fabrication of high efficiency laser diodes. (Al,In)N is an alloy system which offers the potential to fabricate completely lattice matched III-V nitride heterostructures. There has been little work to date on the growth of high quality (Al,In)N and, as a result, many of the fundamental properties of this alloy system, such as bandgap energy, have never been experimentally verified. In this Phase I program, we will examine the feasibility of growing (Al,In)N alloys and (Al,Ga)N/GaN heterostructures by metal organic vapor phase epitaxy (MOVPE). This technology will serve as the foundation for high efficiency UV lasers to be fabricated in Phase II. Phase III will consist of further development and commercialization of these devices.