Collaborative Research: Connecting Mesoscale Dynamics of Metallic Films on Semiconductors to Nanoscale Phenomena

合作研究：将半导体上金属薄膜的介观动力学与纳米尺度现象联系起来

• 批准号: 1710306
• 负责人: Talat Rahman
• 金额: $ 16.23万
• 依托单位: The University of Central Florida Board of Trustees
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1710306&HistoricalAwards=false
• 关键词: Collaborative; Research; Connecting; Mesoscale; Dynamics

Nontechnical AbstractElectronic devices, such as computers and smartphones, are at the heart of our technological society. Such devices currently are based on semiconductor technology, which involves making electrical contacts between metals and semiconductors. By studying and understanding the details of how metals can be deposited onto semiconductor materials, this project will allow the development of novel methods to grow low dimensional nanostructures, such as extremely thin wires and very thin films. The project connects state-of-the-art experiments to observe the growth properties of the materials with sophisticated theoretical techniques using models consisting of tens to millions of atoms to explore the physics governing the predicted properties of the fabricated nanostructures. Working in conjunction, these methods will facilitate the optimal design and creation of these low dimensional nanostructures. Such structures could be very useful in making future electronic devices, thus maintaining the technological leadership of the U.S. in nanotechnology. Students working on the project will not only gain in-depth physical understanding in the exciting research areas involving metal-semiconductor interfaces but also will engage in outreach activities with local K-12 students and teachers with whom the PIs have on-going interactions, especially through the American Physical Society Physics Teacher Education Coalition (APS PhysTEC). All PIs regularly mentor undergraduate researchers and are actively engaged in recruiting women and underrepresented minority students, particularly through the APS Bridge Program.Technical AbstractThis project will study the growth mechanisms of several metal on semiconductor systems. The objectives of this project are controlling the growth of low-dimensional (1D and 2D) nanostructures, elucidating the novel and complex collective diffusion behavior which has been observed for these systems, and understanding how quantum behavior can influence epitaxial growth in order to facilitate the optimal design and fabrication of novel materials. A complementary set of experimental and theoretical techniques will be applied to examine systematically the initial growth stages and structural evolution of Ag, Au, and Pb nanostructures on single crystal surfaces of Ge and Si. The atomic ordering and adatom binding sites, as well as sizes and shapes of formed islands, will be determined by scanning tunneling microscopy (STM) and low energy electron microscopy/diffraction (LEEM/LEED) and compared with predictions from density functional theory (DFT)-based simulations. Unusual collective behavior of millions of atoms and quantum size effects (QSE) will be investigated to elucidate details of the mechanisms. Scanning tunneling spectroscopy (STS) and angle-resolved photoemission spectroscopy (ARPES) will be used to measure local density of states, k-resolved band structure, and quantum well states; these results will be compared with DFT calculations to understand the factors controlling the nanostructure characteristics and to formulate the physical picture about the basic mechanisms and processes for future growth. Bond order potentials (BOP) will be determined for metals bound to semiconductor surfaces and used for self-learning kinetic Monte Carlo (SLKMC) simulations of the growth and movement of islands. These large-scale simulations will improve understanding of the physical origin of the collective motions and suggest additional experimental systems that may display unusual physical phenomena. The use of Si and Ge-based materials would enable rapid development of technological applications for electronic devices.

非技术摘要电子设备，例如计算机和智能手机，是我们技术社会的核心。目前此类设备基于半导体技术，涉及金属和半导体之间的电接触。通过研究和了解金属如何沉积到半导体材料上的细节，该项目将开发出生长低维纳米结构的新方法，例如极细的线和极薄的薄膜。该项目将最先进的实验与复杂的理论技术结合起来，观察材料的生长特性，使用由数千万到数百万个原子组成的模型来探索控制所制造的纳米结构的预测特性的物理原理。这些方法结合起来将有助于这些低维纳米结构的优化设计和创建。这种结构对于制造未来的电子设备非常有用，从而保持美国在纳米技术方面的技术领先地位。从事该项目的学生不仅将在涉及金属-半导体界面的令人兴奋的研究领域获得深入的物理理解，而且还将与当地的 K-12 学生和教师一起参与外展活动，PI 与他们保持着持续的互动，特别是通过美国物理学会物理教师教育联盟 (APS PhysTEC)。所有 PI 都会定期指导本科生研究人员，并积极招募女性和代表性不足的少数族裔学生，特别是通过 APS Bridge 计划。技术摘要该项目将研究半导体系统上几种金属的生长机制。该项目的目标是控制低维（一维和二维）纳米结构的生长，阐明在这些系统中观察到的新颖且复杂的集体扩散行为，并了解量子行为如何影响外延生长，以促进新型材料的优化设计和制造。将应用一套互补的实验和理论技术来系统地研究Ge和Si单晶表面上Ag、Au和Pb纳米结构的初始生长阶段和结构演化。原子排序和吸附原子结合位点以及形成的岛的大小和形状将通过扫描隧道显微镜 (STM) 和低能电子显微镜/衍射 (LEEM/LEED) 确定，并与密度泛函理论 (DFT) 的预测进行比较）基于模拟。将研究数百万个原子的异常集体行为和量子尺寸效应（QSE），以阐明其机制的细节。扫描隧道光谱（STS）和角分辨光电子光谱（ARPES）将用于测量局域态密度、k分辨能带结构和量子阱态；这些结果将与 DFT 计算进行比较，以了解控制纳米结构特征的因素，并制定有关未来生长的基本机制和过程的物理图景。键序势 (BOP) 将确定与半导体表面结合的金属，并用于岛的生长和运动的自学习动力学蒙特卡罗 (SLKMC) 模拟。这些大规模模拟将增进对集体运动物理起源的理解，并提出可能显示不寻常物理现象的额外实验系统。硅基和锗基材料的使用将促进电子设备技术应用的快速发展。

项目成果

Dominant contributions to the apparent activation energy in two-dimensional submonolayer growth: comparison between Cu/Ni(111) and Ni/Cu(111)

二维亚单层生长中表观活化能的主要贡献：Cu/Ni(111) 和 Ni/Cu(111) 之间的比较

• DOI: 10.1088/1361-648x/ab9b50
• 发表时间: 2020-10
• 期刊: Journal of Physics: Condensed Matter
• 作者: Alberdi;Acharya, Shree Ram;Rahman, Talat S;Arnau, Andres;Gosálvez, Miguel A
• 通讯作者: Gosálvez, Miguel A