Atomic Modeling and Controlled Formation of III-V Nanopillars by Catalyst-Free Growth Mode

技术：该项目寻求对图案化纳米管MOCVD外延的表面动力学和晶体形成的基本了解。具体目标是建立一个物理模型来预测吸附原子在III-V半导体纳米柱上的择优掺入，并通过实验验证和优化纳米柱结构的形成和特征。该项目有三个主要组成部分：1)3D表面动力学的实验可验证预测物理模型，2)相关的纳米管表征和分析模拟，以及3)在预定位置上控制的优先纳米管外延。与使用催化金属纳米颗粒(例如，Au)生长的半导体纳米线不同，这些纳米管柱在没有催化剂的情况下生长在带有光刻定义的纳米管的掩膜基板上。这种方法避免了金属污染，并提供了纳米管的放置，以及随后的器件掩模配准。在从头算密度泛函理论、Wulff理论的基础上，结合弹性应变和热动力学成分，对原子表面动力学进行了模拟，将吸附原子的择优结合与纳米晶面、表面能和生长参数联系起来。将进行结构、组成、电学和光学性质的相关测量，并结合数学模拟提取纳米管的性质，包括表面态密度、载流子动力学和量子效应。非技术性：该项目解决与电子和光子学技术相关的材料科学专题领域的基础研究问题。正在研究的材料和纳米结构可能成为先进光电子器件的基本组成部分。该项目强调通过实验室参与、辅助性课程开发和以科学为重点的社区K-12参与，在培训大学预科、本科生和研究生方面进行综合教育和研究。这两个私人投资机构都坚定地致力于纳入和扩大代表不足的少数群体对本科生和研究生研究的参与。对本科生实验室就业的支持已编入预算，并制定了一项计划，通过学生URM(代表不足的少数族裔)社团和历史上的URM学院，以及通过加州大学洛杉矶分校工程卓越和多样性中心(CEED)，集中招聘。技术转让是通过与几家公司和国家实验室合作进行的。

Technical: This project seeks fundamental understanding of surface kinetics and crystal formation with respect to patterned nanopillar MOCVD epitaxy. Specific goals are to establish a physical model to predict preferential adatom incorporation on III-V semiconductor nanopillars, and to experimentally verify and optimize the formation and characteristics of the nanopillar structures. The project has three primary components: 1) experiment verifiable predictive physical modeling of 3D surface dynamics, 2) correlated nanopillar characterizations and analytical simulations, and 3) controlled preferential nanopillar epitaxy on predetermined sites. Unlike semiconductor nanowires grown using catalytic metal nanoparticles (e.g., Au), these nanopillars are grown without catalysts on masked substrates with lithographically defined nanopatterns. This approach obviates metallic contamination and provides nanopillar placement, along with subsequent device mask registration. Simulation of atomic surface dynamics, based on ab-initio density functional theory, Wulff's theory and integrated with elastic strain and thermal kinetics components, will be conducted to relate preferential adatom incorporation to nanopillar faceting, surface energy, and growth parameters. Correlated measurements of structural, compositional, electrical, and optical properties will be performed, and combined with mathematical simulation for extraction of nanopillar properties including surface state density, carrier dynamics, and quantum effects. Non-technical: The project addresses basic research issues in a topical area of materials science with technological relevance in electronics and photonics. The materials and nanostructures being studied can potentially serve as basic building blocks for advanced optoelectronic devices. The project emphasizes integrated education and research in training of pre-college, undergraduate, and graduate students through laboratory participation, complementary coursework development, and scientifically focused community K-12 involvement. Both PIs are strongly committed to inclusion and broadening participation of under-represented minority groups in undergraduate and graduate research. Support for undergraduate laboratory employment is budgeted and a plan is in place for focused recruiting through student URM (underrepresented minorities) societies and historically URM colleges, as well through the UCLA Center for Engineering Excellence and Diversity (CEED). Technology transfer is included through collaboration with several companies and national laboratories.