SBIR Phase I: Enhanced Reflectivity GEMM Materials for High-Efficiency and Low-Cost III-Nitride LED Technology

This Small Business Innovation Research Phase I project will investigate the feasibility of using dopants to significantly improve the reflectivity of a novel grown epitaxial-metal-mirror (GEMM) technology to increase light-emitting diode (LED) device performance and substantially reduce the cost of manufacturing high-brightness III-nitride LEDs. The GEMM technology provides an integrated mirror directly into the epitaxial layers of the LED device, which simplifies manufacturing, reduces cost, and improves yield. Furthermore, the GEMM allows for very precise control over the placement of the mirror in order to take advantage of micro-half-cavity effects. The reflectivity of the first-generation GEMM materials for blue wavelengths is approximately 70%-75% and therefore to further improve the performance and efficiency of the GEMM for blue LEDs and drive market adoption of GEMM-LEDs, we will investigate doping of the GEMM materials to shift the reflectivity spectrum to shorter wavelengths. It is anticipated that these doped-GEMM materials will exhibit reflectivities of 90% or greater in the range of 450 to 460 nm, leading to significantly improved LED performance, while simultaneously reducing manufacturing costs, and will ultimately drive solid-state lighting to become truly commercially competitive. The broader impact/commercial potential of this project will be the availability of highly energy-efficient solid-state lighting for general consumer use at a cost that is competitive with compact-fluorescent lamps. Currently, LED-based lamps are 5 to 10 times the cost of comparable compact-fluorescent lamps. The market pull for the GEMM technology relies on a projected 35% to 68% lower production cost per lumen for LED chips, which will motivate LED chip manufacturers to purchase GEMM substrates for device growth. Downstream manufactures of LED-based fixtures and manufacturers that integrate light emitters into their products would also greatly benefit from the lower cost and higher performance of GEMM-LEDs. The successful demonstration of enhanced GEMM materials for LEDs during this project has the potential to accelerate the availability of cost-competitive solid-state lighting and drive consumers to embrace LED-based general lighting. In turn, the acceleration of widespread adoption of solid-state LED-based lighting has the potential to reduce the nation's dependence on foreign energy, reduce domestic greenhouse gas emissions, and revitalize the economy of the United States through the creation of "green" jobs and continued technological leadership.