High-Resolution Morphological Control of Silicon Nanowires for Bottom-Up Photonics and Plasmonics

技术描述：本项目旨在开发一种自下而上的高分辨率控制硅纳米线形态的方法。传统上，半导体纳米线被限制为圆柱形、轴对称结构，然而，许多纳米线的新技术应用可以通过一种方法来打破轴对称，并沿着纳米线轴线产生良好控制的形状。为了实现这一目标，本研究项目研究了硅纳米线的原位化学掺杂和与掺杂相关的湿化学蚀刻工艺的基本方面。这项研究有望对在气-液-固和气-固-固两种纳米线生长过程中掺杂掺杂剂的引入产生根本性的见解。通过系统地探索湿化学蚀刻速率对纳米线掺杂的依赖性，该项目也有望实现纳米线的合成，其中轴向形貌在几纳米到几微米的长度范围内进行调制。通过实验和有限元模拟相结合的方法研究了形貌控制纳米线的光吸收和散射特性，以确定其在纳米光子学和等离子体学领域的潜在技术应用。非技术描述：大多数发展良好的半导体技术需要在微观尺度上对材料进行图形化。半导体纳米线通常缺乏纳米尺度的图像化能力，这是许多应用所必需的。该项目旨在开发一种简单的化学方法，将高分辨率图案编码到由硅组成的纳米线中。这个项目的结果有望大大扩展我们对纳米线生长过程的基本理解。研究了金属丝的光学特性，以确定它们在利用光进行信息处理和计算应用的技术中的潜在应用。这个项目被整合到中学到研究生的教育和推广活动中。全年参与研究的研究生和本科生在跨学科的环境中接受培训，该环境将化学、工程、物理和材料科学的概念联系起来。通过一个夏季拓展项目，来自传统上代表性不足的群体的中学生和高中生将体验强调原创概念和发现的实践研究。整个项目旨在促进具有不同背景的学生之间的合作，使用来自物理科学各个领域的概念和技术。

Technical Description: This project aims to develop a bottom-up method for high-resolution control of silicon nanowire morphology. Semiconductor nanowires have traditionally been limited to cylindrical, axially symmetric structures, yet many new technological applications for nanowires could be enabled with a method to break the axial symmetry and produce well-controlled shapes along the nanowire axis. In pursuit of this goal, this research project investigates fundamental aspects of in-situ chemical doping of silicon nanowires and doping-dependent wet-chemical etching processes. The research is expected to yield fundamental insights into the incorporation of dopants during both vapor-liquid-solid and vapor-solid-solid nanowire growth processes. By systematically exploring the dependence of wet-chemical etch rates on nanowire doping, this project is also expected to enable the synthesis of nanowires in which the axial morphology is modulated on length scales ranging from a few nanometers to several micrometers. The optical absorption and scattering characteristics of the morphologically-controlled nanowires are studied through a combination of experiment and finite-element simulations to determine their potential technological application in the areas of nanophotonics and plasmonics.Non-technical Description: Most well-developed semiconductor technologies require the patterning of materials on a microscopic scale. Semiconductor nanowires often lack the nanometer-scale patterning capability, which is necessary for many applications. This project aims to develop a simple chemical method to encode high-resolution patterns into nanowires composed of silicon. The results from this project are expected to substantially expand our fundamental understanding of nanowire growth processes. The optical properties of the wires are studied to determine their potential application for technologies that use light for information processing and computing applications. This project is integrated into educational and outreach activities involving middle-school through graduate-level students. Graduate and undergraduate students involved in the research on a year-round basis are trained in a cross-disciplinary environment that bridges concepts from chemistry, engineering, physics, and materials science. Through a summer outreach program, middle- and high-school students from traditionally underrepresented groups experience hands-on research emphasizing original concepts and discovery. The overall project is designed to foster collaboration between students with a diverse range of backgrounds using concepts and techniques derived from all areas of the physical sciences.