NER: AlGaN Quantum Dots for Short Wavelength Luminescent Devices

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This proposal was received in response to Nanoscale Science and Engineering initiative, NSF 01-157, category NER. The objective of the proposed work is to explore new methods for wet chemical preparation of GaN and AlGaN quantum dots. While extensive research has been conducted on metal chalcogenide quantum dots in recent years, comparatively little research activity has been directed toward studying III-nitride quantum dots. The primary reason for this neglect has been the relative difficulty of preparing III-nitride quantum dots that are isolated, monodisperse, and manipulable. The proposed new synthetic method is based on a simple exchange reaction carried out in a coordinating solvent or in a non-coordinating solvent containing an adsorbate that stabilizes growing nanoparticles and protects them from flocculation. The advantages of this method over previous routes to GaN are inexpensive starting materials, mild reaction conditions, extension to other III-nitrides and their alloys, and facile processing of the product material. This ease of processing is key to eventually incorporating these quantum dots into thin film electronic and optical devices. The specific aims of this project are to investigate the effects of different reaction parameters (temperature, solvent, and other additives) on the rate and yield of the reaction and to discover the optimal methods for isolation of the desired product. The successful completion of this work is expected to enable research and development of new composite materials and devices containing III-nitride quantum dots as integral, functional components. The experimental work will be performed by an undergraduate research assistant and two graduate research assistants under the guidance of the PI and one of the co-PIs. These students will benefit from the highly interdisciplinary nature of the research and exposure to a wide variety of techniques both synthetic and analytical. These include dry box, vacuum line, and soxhlet techniques as well as a variety of electronic, structural, and particle size characterization methods. The two students will initially focus on different aspects of the project (synthesis vs. characterization), but by the end of the year, both will have gained experience with the full range of techniques being used.