Short Wavelength UV LEDs Based on Bulk Nitride Substrates

DESCRIPTION (provided by applicant): Modern biomedical instrumentation relies on ultraviolet (UV) light sources to implement a broad range of detection techniques. The long-term goal of the proposed effort is the development of solid-state UV light emitting diodes (UV LEDs) as a replacement for existing lamp sources at wavelengths shorter than 360 nm, where commercial solid-state devices do not exist. The proposed approach is based on the fabrication of UV LEDs in the aluminum gallium nitride (AIGaN) material system on a recently-developed bulk single-crystal aluminum nitride (AIM) substrate. The unique properties of this AIM substrate, including its close lattice- match to AIGaN alloys and its exceedingly low defect density, enable the manufacture of LEDs with shorter wavelength, higher efficiency, higher brightness, and longer lifetime than those fabricated on alternative substrate materials. The Phase I program is to design and demonstrate a UV LED with emission at 340 nm. A novel epitaxial structure in the AIGaN system will be designed, modeled, grown and characterized. Then devices will be fabricated and tested. At the 340 nm wavelength and shorter, such UV LEDs will offer improved efficiency, compactness, reliability, and cost relative to existing lamps, enhancing the performance and utility of biomedical research tools and perhaps fostering a new generation of compact microfluidic instruments. Ultimately, this will enable a greater understanding of the biological mechanisms that underlie human health, the discovery of new therapies and diagnostics, and more precise control of pharmaceutical manufacturing processes and drug quality.