NER: AlGaN Quantum Dots for Short Wavelength Luminescent Devices

该提案是对NSF 01-157类纳米科学与工程倡议的响应。这项工作的目的是探索湿法化学制备GaN和AlGaN量子点的新方法。虽然近年来人们对金属硫化物量子点进行了广泛的研究，但针对III-氮化物量子点的研究活动相对较少。这种忽视的主要原因是制备隔离、单分散和可操作的III-氮化物量子点的相对困难。所提出的新的合成方法是基于在配位溶剂或非配位溶剂中进行的简单交换反应，所述非配位溶剂包含稳定生长的纳米颗粒并保护其免受絮凝的吸附剂。与以前合成GaN的方法相比，这种方法的优点是原料便宜，反应条件温和，可推广到其他III-氮化物及其合金，并且产品材料易于加工。这种加工的简便性是最终将这些量子点整合到薄膜电子和光学设备中的关键。本项目的具体目的是研究不同的反应参数(温度、溶剂和其他添加剂)对反应速度和产率的影响，并找到分离所需产品的最佳方法。这项工作的成功完成有望使研究和开发新的复合材料和设备成为可能，这些材料和设备将III-氮化物量子点作为完整的功能组件。实验工作将由一名本科生研究助理和两名研究生研究助理在主计长和一名副主计长的指导下进行。这些学生将受益于研究的高度跨学科性质，并接触到各种各样的技术，包括合成和分析。这些技术包括干盒、真空线和索氏技术，以及各种电子、结构和粒度表征方法。两名学生最初将专注于项目的不同方面(合成与表征)，但到今年年底，两人都将获得所使用的各种技术的经验。

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.