Investigation of Growth and Dopant Incorporation in Silicon Carbide Nanowires

非技术描述：半导体纳米线是一种直径在几十纳米数量级的高纵横比棒，由于其预期(在某些情况下观察到)新颖的光学、热、电和机械行为，近年来受到了极大的关注。到目前为止，由于材料的技术相关性和合成的相对简单，硅(Si)纳米线一直是研究最广泛的。然而，一些关键的应用，如高效的电化学存储设备和高亮度的微型中子源，突显了硅纳米线的局限性和对更强大的材料系统的需求。选择碳化硅(碳化硅)纳米线进行这些研究，是因为这种材料具有特殊的物理化学稳定性。本研究旨在对碳化硅纳米线的生长机理及控制其形态和电学性能的参数有一个基本的了解。技术细节：采用镍催化化学气相沉积法制备碳化硅纳米线，以氨气为掺杂剂。主要的分析技术包括高分辨率电子显微镜(用于详细的结构研究)、拉曼光谱(用于结构、振动和光学性质)、原子探针层析(用于亚纳米分辨率的化学成分测绘)和场效应晶体管测量(用于电学特性，包括费米能级位置和载流子浓度和迁移率)。从根本上讲，这项研究使人们能够更好地了解生长参数(如催化剂、生长温度、掺杂前体)与碳化硅纳米线的结构、形态和电学性质之间的相互作用。从应用的角度来看，这项研究强调了用于真空电子发射器、耐腐蚀电荷存储器件以及其他能源、传感和恶劣环境应用的定制掺杂合成碳化硅纳米线的关键因素。该项目为研究生和本科生提供核心培训。目前正在开展各种外联活动，包括代表人数不足的学生参与研究。这项工作的成果正在被纳入研究人员向公众发表的演讲中，并通过各种方式广泛传播，如参考期刊、会议、讲座和演示。该项目由材料研究部电子与光子材料(EPM)和陶瓷(CER)项目共同资助。

NON-TECHNICAL DESCRIPTION: Semiconducting nanowires, high aspect ratio rods with diameters of order tens of nanometers, have received much attention in recent years, due to their anticipated (and in some cases observed) novel optical, thermal, electrical, and mechanical behavior. To date, silicon (Si) nanowires have been the most extensively studied owing both to the technological relevance of the material and to the relative simplicity of the synthesis. However, a number of critical applications, such as high-efficiency electrochemical storage devices and high brightness miniature neutron sources, highlight the limitations of Si nanowires and the need for more robust materials systems. Silicon carbide (SiC) nanowires were chosen for these studies because of the exceptional physicochemical stability of this material. This research project aims to gain a fundamental understanding of the growth mechanism of silicon carbide nanowires and the parameters that control their morphological and electrical properties.TECHNICAL DETAILS: The specific SiC nanowire synthetic approach chosen is Ni-catalyzed chemical vapor deposition from single precursor methyltrichlorosilane and with ammonia as a dopant. The primary analytical techniques include high-resolution transmission electron microscopy (for detailed structural studies), Raman spectroscopy (for structural, vibrational, and optical properties), atom probe tomography (for chemical composition mapping with sub-nm resolution) and field-effect transistor measurements (for electrical characterization, including the Fermi level position and carrier concentration and mobility). From a fundamental point of view, this research is enabling a better understanding of the interplay between the growth parameters (e.g., catalyst, growth temperature, dopant precursor) and the structural, morphological and electrical properties of SiC nanowires. From the applied point of view, the research is highlighting the key factors for synthesizing SiC nanowires with tailored doping for such applications as emitters for vacuum electronics, corrosion resistant charge storage devices, and other energy, sensing, and harsh environment applications. The project is providing core training for graduate and undergraduate students. A variety of outreach activities, including the participation of underrepresented students in research, are underway. The results of this work are being incorporated into talks given to the general public by the researchers and are also being widely disseminated through a variety of means such as refereed journals, conferences, lectures, and demonstration.This project is co-funded by the Electronic and Photonic Materials (EPM) and Ceramics (CER) Programs in the Division of Materials Research (DMR).