STTR Phase I: Ammonothermal Growth of Doped Aluminum Gallium Nitride Single Crystals for Energy Efficient Solid State Lighting and Tunable LED?s

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This Small Business Technology Transfer Phase I project will address the problem of a multifunctional wide band-gap aluminum gallium nitride single crystal substrate that will enable low-defect, high-performance epitaxial growth. Since much of the energy consumed in the U.S. used for traditional lighting is wasted as heat, solid-state lighting (SSL) has the potential to reduce our energy consumption dramatically. The technology is lacking a critical material that will allow production of high efficiency devices however. Single crystals of AlGaN substrate will enable the production of a tunable bandgap material with a variable band-edge from the visible to the UV range, including the solar blind region between 250-280nm. In addition to solid-state lighting, such a multifunctional material can be used for UV-Vis diode lasers and UV photodetectors in the solar blind region. This technology exploits six years of joint engineering and design of a proven, commercially operational autoclave from APC and Clemson University. The technology can contain the high temperatures and pressures required for hydrothermal growth of oxide crystals (700 C and 4kbar). To accomplish the objectives of Phase I the current hydrothermal model autoclave design will be adapted to work for ammonothermal crystal growth. Broader ImpactsThis Small Business Technology Transfer Phase I project will support the next generation of crystal growth technology in the United States. It will develop a commercially viable route to a key material in solid-state lighting, UV-Vis diode lasers and UV photodetection. The crystal growth industry has exited the United States, leaving a significant gap in the ability to produce strategically important solids onshore. The technical skills to grow single crystals for important materials have decreased significantly in the US. This project will develop a next generation technology that will contribute to US self-sufficiency in a strategic area of materials science. The project will also lead to training of a young postdoctoral fellow in the field of crystal growth, an area that is underdeveloped in the US. The project will also contribute to energy self-sufficiency. Solid-state lighting is expected to save significant energy by improving efficiency and minimizing waste heat. A primary limitation to widespread introduction of solid-state lighting is lack of suitable substrates. This project will provide materials that will enable much high efficiency and long life solid state lighting as well as solid state diode lasers and various other technologies that will provide competitive advantage to the US.