Doping Profiles in Semiconductor Nanowires

技术：半导体纳米线是电子和光子学技术的潜在变革材料，掺杂和成分调制是半导体器件的基础。该项目的目标是了解和控制硅和锗纳米线中的掺杂率和结型，从而为纳米线器件的制造奠定基础。采用原子探针层析成像技术绘制了单掺杂原子灵敏度的气-液-固和气-固-固生长纳米线中给体和受体掺杂原子的三维分布。不同的催化剂和生长条件将被用来了解影响掺杂率的热力学和动力学因素。这样的理解有望为径向结（如核-壳结构）和轴向结确立结突然性的最终极限。电输运和扫描探针测量，包括扫描开尔文探针显微镜和扫描光电流显微镜，用于确定活性掺杂剂的比例和测量掺杂剂同质结的电分布。合成、成分映射和电学表征的综合活动允许区分纳米级掺杂物分布产生的电学性质和纳米/中观尺度上修改筛选产生的电学性质。非技术：该项目涉及材料科学主题领域的基础研究问题，具有高技术相关性。预计该活动将推动对半导体行业至关重要的材料和计量。该项目整合了研究和教育，通过PI和他的研究生参与当地一所高中的一个新的学生调查研究项目，以及高级工艺设计课程的学生团体参与纳米线加工和结构关系的发现和优化，促进了发现和理解。

Technical: Semiconductor nanowires are potentially transformative materials for electronics and photonics technologies, and doping and composition modulation are the foundation of semiconductor devices. The objective of this project is to understand and control dopant incorporation rates and junction profiles in silicon and germanium nanowires in order to establish a foundation for nanowire device fabrication. Atom probe tomography is used to map the 3-dimensional distribution of donor and acceptor dopant atoms in vapor-liquid-solid and vapor-solid-solid grown nanowires with single dopant atom sensitivity. Varied catalysts and growth conditions will be employed to understand the thermodynamic and kinetic factors that influence doping rates. Such understanding is expected to establish the ultimate limits of junction abruptness for both radial junctions, as in core-shell structures, and axial junctions. Electrical transport and scanning probe measurements, including scanning Kelvin probe microscopy and scanning photocurrent microscopy, are used to determine the fraction of active dopants and measure the electrical profiles of dopant homojunctions. The integrated activities of synthesis, composition mapping, and electrical characterization permit distinctions between electrical properties that arise from nanoscale dopant distributions and those that arise from modified screening on the nano/meso scale. Non-technical: The project addresses basic research issues in a topical area of materials science with high technological relevance. The activity is expected to advance materials and metrology of critical importance to the semiconductor industry. The project integrates research and education by advancing discovery and understanding through involvement of the PI and his graduate students in a new Student Investigative Research program at a local high school and engaging student groups from a senior level process design course in the discovery and optimization of nanowire processing-structure relationships.