Germanium Nanostructures for Efficient Silicon-Compatible Optoelectronics

用于高效硅兼容光电器件的锗纳米结构

• 批准号: 1203186
• 负责人: Domenico Pacifici
• 金额: $ 40万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1203186&HistoricalAwards=false
• 关键词: Germanium; Nanostructures; Efficient; Silicon; Compatible

This project is jointly funded by the Electronic and Photonic Materials Program (EPM) in the Division of Materials Research (DMR) and the Energy, Power, and Adaptive Systems Program (EPAS) in the Division of Electrical, Communications and Cyber Systems (ECCS).Technical Description: Efficient optoelectronic active materials, based on confined germanium quantum dots and germanium/silicon quantum wires, promise enhanced photoconversion mechanisms useful for chip-compatible photodetectors and solar cells with broadband absorption. This project focuses on two interrelated classes of optoelectronic materials and devices: (1) a close-packed array of Ge quantum dots for high-efficiency photodetectors and (2) Ge/Si heteronanowires for tandem solar cells. Materials properties of Ge quantum dots (such as concentration, crystallinity and surface passivation) are directly correlated to optoelectronic functionalities and optimized to improve the photodetection speed while retaining high responsivity. The response time and gain mechanisms are studied using time-resolved measurements as well as theoretical modeling of charging and inter-quantum-dot hopping. For the second class of materials and devices, the Ge/Si nanowires are grown using the vapor-liquid-solid technique to overcome lattice mismatch limitations. The transport and optical response of individual heteronanowires are correlated with nanowire diameter, length, doping and composition, and are used to predict the collective behavior of dense nanowire arrays with improved spectral coverage and reduced reflectivity. Simulations are performed to match the short-circuit currents in the Ge and Si sections in order to achieve enhanced photoconversion efficiency.Non-technical Description: This research project is on light-matter interactions in germanium-based nanostructures, including quantum dots and quantum wires. These nanostructures combine attractive physical properties enabled by more efficient light-matter interaction at the nanoscale. Specifically, the project seeks to use these nanomaterials for higher-efficiency photodetectors and broadband solar cells. The research has educational impact in and out of the classroom at Brown University. It includes long-term collaboration between faculty and graduate students at Brown University and scientists at the Los Alamos National Laboratory, on nanowire growth. Undergraduates also work on parts of the research. In addition, solar energy-based K-12 outreach activities are expanded and local high-school students participate in laboratory summer research.

该项目由材料研究部（DMR）的电子和光子材料计划（EPAS）和电气、通信和网络系统部（ECCS）的能源、电力和自适应系统计划（EPAS）共同资助。技术描述：基于受限锗量子点和锗/硅量子线的高效光电活性材料，有望增强的光转换机制，可用于芯片兼容的光电探测器和具有宽带吸收的太阳能电池。该项目主要关注两类相互关联的光电材料和器件：（1）用于高效光电探测器的Ge量子点密排阵列和（2）用于串联太阳能电池的Ge/Si异质纳米线。Ge量子点的材料特性（如浓度、结晶度和表面钝化）与光电功能直接相关，并被优化以提高光电探测速度，同时保持高响应度。响应时间和增益机制进行了研究，使用时间分辨测量以及理论建模的充电和量子点间跳跃。对于第二类材料和器件，Ge/Si纳米线使用气-液-固技术生长以克服晶格失配限制。个别heteronanowires的传输和光学响应与纳米线的直径，长度，掺杂和组合物，并被用来预测的集体行为的密集纳米线阵列，提高光谱覆盖率和降低反射率。模拟进行匹配的短路电流在锗和硅的部分，以实现增强的photoconversionefficiency.Non-technical描述：本研究项目是在锗基纳米结构，包括量子点和量子线的光物质相互作用。这些纳米结构联合收割机结合有吸引力的物理性能，使更有效的光-物质相互作用在纳米级。具体而言，该项目旨在将这些纳米材料用于更高效的光电探测器和宽带太阳能电池。这项研究在布朗大学的课堂内外都有教育影响。它包括布朗大学的教师和研究生与洛斯阿拉莫斯国家实验室的科学家在纳米线生长方面的长期合作。本科生也参与了部分研究。此外，还扩大了以太阳能为基础的K-12外联活动，当地高中生参加了实验室夏季研究。