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柱MOCVD外延的表面动力学和晶体形成的基本理解。具体目标是建立一个物理模型，预测优先吸附原子纳入III-V族半导体纳米柱，并通过实验验证和优化的纳米柱结构的形成和特性。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的预测物理建模，2）相关纳米柱表征和分析模拟，以及3）预定位置上的受控优先纳米柱外延。与使用催化金属纳米颗粒生长的半导体纳米线（例如，Au），这些纳米柱在没有催化剂的情况下生长在具有光刻限定的纳米片的掩蔽衬底上。这种方法消除了金属污染，并提供了纳米柱放置，沿着随后的器件掩模配准。原子表面动力学的模拟，从头算密度泛函理论的基础上，武尔夫的理论和弹性应变和热动力学组件集成，将进行相关的优先吸附原子纳入纳米柱刻面，表面能，和生长参数。将进行结构，成分，电学和光学特性的相关测量，并结合数学模拟提取纳米柱特性，包括表面态密度，载流子动力学和量子效应。非技术性：该项目涉及材料科学专题领域的基础研究问题，与电子和光子学技术相关。正在研究的材料和纳米结构可以作为先进光电器件的基本构建模块。该项目强调通过实验室参与，补充课程开发和科学重点社区K-12参与的大学预科，本科和研究生培训的综合教育和研究。这两个PI都坚定地致力于包容和扩大代表性不足的少数群体在本科和研究生研究的参与。对本科实验室就业的支持是有预算的，并计划通过学生URM（代表性不足的少数民族）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与多样性中心（CEED）进行重点招聘。技术转让包括通过与若干公司和国家实验室的合作进行。

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.