Molecular Routes to Nanocrystalline GaN and GaN Films

该奖项授予明尼苏达大学的Wayne Gladfelter，由材料研究部化学高级材料项目和电子材料项目支持。这项研究的两个目标是开发新的氮化镓前体，这将允许更低的加工温度，以及开发用于生长确定尺寸的纳米晶体颗粒的合成方案。新的挥发性前体将主要基于氢化镓配合物和有机叠氮镓。利用薄膜生长动力学和同位素标记来研究沉积的化学反应机理。用氘对前体进行特殊标记，并使用前反冲弹性散射光谱法同时对H和D进行谱分析，可以确定膜中氢的来源。一种新的链终止方法将被用来控制纳米晶体的粒径使用已知的和新的氢化镓配合物。在这种方法下，非活性链终止基团将覆盖在颗粒上的镓和氮基团的表面，防止进一步生长或团聚。氮化镓是能够吸收或发射蓝光的光电器件的有吸引力的候选者。本研究将提供氮化镓薄膜结构随时间、温度、压力和前驱体结构的演化图。通过将这些数据与沉积机理的研究相结合，将建立生长化学与薄膜组成和结构之间的关键联系。

This award to Wayne Gladfelter at the University of Minnesota is supported by the Advanced Materials Program in Chemistry and the Electronic Materials Program in the Division of Materials Research. The twofold goals of the research are the development of new precursors to gallium nitride which will permit lower processing temperatures, and the development of synthetic schemes for the growth of nanocystalline particles of defined size. New volatile precursors will be based primarily on gallium hydride complexes and organogallium azides. The chemical reaction mechanism of the deposition will be examined using film growth kinetics and isotopic labeling. Specific labeling of the precursors with deuterium and simultaneous profiling of H and D using forward recoil elastic scattering spectrometry will permit the determination of the source of hydrogen incorporation in the films. A novel chain-termination approach will be used to control nanocrystal particle size using known and new gallium hydride complexes. Under this approach, unreactive chain terminating groups will coat the surface of the gallium and nitrogen groups on the particles and prevent further growth or agglomeration. Gallium nitride is an attractive candidate for optoelectronic devices capable of absorbing or emitting blue light. This research will provide a picture of the evolution of gallium nitride film structure as a function of time, temperature, pressure and precursor structure. By correlating these data with studies of the deposition mechanism, the critical connection between growth chemistry and film composition and structure will be made.