Low-Temperature Epitaxy of Gallium Nitride Thin Films

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The research objective of this award is to elucidate the mechanisms responsible for a low-temperature growth process of high-quality gallium nitride (GaN) films with low thermal impact on substrates. The project will develop a laser-assisted metalorganic vapor phase epitaxy (L-MOVPE) process that can enhance the chemical reactions in epitaxy of GaN thin films with low substrate temperatures. A wavelength-tunable CO2 laser, with a wavelength tunability from 9.2 to 10.9 micrometers, will be used to resonantly excite NH3 molecules for promoting chemical reactions to facilitate and maximize the GaN epitaxy process. The research approach progresses from mechanism study of resonant excitations of precursor molecules, to growth of high-quality GaN epilayers on different substrates for a wide range of applications. Deliverables include an L-MOVPE system configured for synthesis of GaN thin films and other functional materials, documentation of research results, and engineering student education.If successful, the results of this research will realize low-temperature growth of high-quality GaN films with high energy-coupling efficiency and low thermal impact on substrates. In terms of applications, the proposed method can provide a novel approach of GaN epitaxy on sapphire or SiC substrates for electronic, optoelectronic, chemical, and biological applications. The successful completion of this project will impact the scientific research of laser-controlled chemical processes by resonant excitation of precursor molecules. Practically, the proposed method is expected to provide a novel approach to synthesizing functional materials at lower temperature with high energy-coupling efficiency. The research results will also contribute to productivity improvement, energy savings, and environmental protection in related industries that rely on high-temperature chemical processes to fabricate compound semiconductors. Graduate and undergraduate students will benefit through involvement in the research and classroom instruction. The engagement of K-12 students and teachers in this project will also establish new partnerships between the University and K-12 schools.