EAGER: Understanding Carrier Multiplication in Black Phosphorus for High-Gain MWIR Avalanche Photodiodes

EAGER：了解高增益中波红外雪崩光电二极管的黑磷中的载流子倍增

• 批准号: 1648782
• 负责人: Steven Koester
• 金额: $ 12.5万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-15 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1648782&HistoricalAwards=false
• 关键词: EAGER; Understanding; Carrier; Multiplication; Black

Black phosphorus is an emerging "two-dimensional" semiconductor material with many extraordinary optical and electronic properties. In particular, black phosphorus has strong optical absorption in the mid-infrared wavelength range, has high electrical current carrying capacity, and can be transferred onto a variety of substrates in layers only a few nanometers thick. For these reasons, black phosphorus could be a revolutionary platform for adaptable infrared imagers and optical communications systems. However, in order to achieve this promise, the process by which charge carriers multiply to create gain must be understood. This project seeks to understand one such gain mechanism, avalanche multiplication through impact ionization, which to date, as not been studied in black phosphorus. This basic physical mechanism will be studied by fabricating nanoscale device structures which will be tested using steady-state and time-dependent electrical measurements as well as optical techniques. These studies can provide fundamental understanding of impact ionization that will be important to realize new types of infrared imaging systems with higher sensitivity and tunability, as well as lower cost, compared to state-of-the-art solutions. The learning from this project will also be broadly applicable to a wide range of other devices using black phosphorus, including light emitters, logic and memory devices and even sensors. In this way, this work could help to realize a transformative technological platform for high-performance, low-cost flexible imagers and electronics. The program will also incorporate training for graduate and undergraduate students in nanoelectronics, and provides natural opportunities for hands-on activities for students at the primary and secondary educational level to illustrate nanoscience concepts.The technical goals of this research program are to evaluate and understand the process of impact ionization in black phosphorus and to analyze the avalanche gain mechanism in photodiodes made using this material. These goals will be met by using high-precision electron-beam lithography to fabricate metal-semiconductor-metal device structures on exfoliated black phosphorus and then performing high-field transport measurements to extract the ionization coefficients for both electrons and holes. Avalanche gain in black phosphorus will also be characterized by illuminating the devices with near-band-edge light and using spatially-mapped photocurrent characterization. This work is intellectually significant in that it is expected to provide extensive fundamental insight into high-electric-field transport in black phosphorus. In particular, it will allow for an understanding of impact ionization, a fundamental process that is critical for the operation of nearly any practical device made from this material, including photodetectors, but also logic, memory and sensing transistors. Furthermore, this project will help to determine the means by which excess noise created from the combined avalanching of electrons and holes can be suppressed in black phosphorus in an analogous way to literature reports on germanium. This learning could ultimately lead to ground-breaking, low-cost, multi-spectral communication and imaging systems with improved speed and sensitivity compared to current solutions.

黑磷是一种新兴的“二维”半导体材料，具有许多非凡的光学和电子特性。特别是，黑磷在中红外波长范围内具有很强的光吸收，具有很高的电流承载能力，并且可以以仅几纳米厚的层转移到各种衬底上。由于这些原因，黑磷可能成为适应性强的红外成像仪和光通信系统的革命性平台。然而，为了实现这一承诺，必须了解电荷载流子倍增以产生增益的过程。该项目旨在了解这样一种增益机制，即通过碰撞电离的雪崩倍增，迄今为止，还没有在黑磷中研究过。这一基本的物理机制将通过制造纳米级器件结构来研究，这些器件结构将使用稳态和随时间变化的电学测量以及光学技术进行测试。这些研究可以提供对碰撞电离的基本理解，这对于实现与最先进的解决方案相比具有更高灵敏度和可调谐性以及更低成本的新型红外成像系统至关重要。从这个项目中学到的知识也将广泛适用于使用黑磷的各种其他设备，包括光发射器，逻辑和存储设备，甚至传感器。通过这种方式，这项工作可以帮助实现高性能，低成本的灵活成像器和电子产品的变革性技术平台。该项目还将为研究生和本科生提供纳米电子学方面的培训，并为小学和中学教育水平的学生提供实践活动的自然机会，以说明纳米科学概念。该研究项目的技术目标是评估和理解黑磷的碰撞电离过程，并分析使用这种材料制成的光电二极管的雪崩增益机制。这些目标将通过使用高精度电子束光刻在剥落的黑磷上制造金属-半导体-金属器件结构，然后进行高场传输测量以提取电子和空穴的电离系数来实现。雪崩增益黑磷也将其特征在于照明的设备与近带边光，并使用空间映射的光电流特性。这项工作是智力上的意义，因为它预计将提供广泛的高电场运输黑磷的基本见解。特别是，它将允许理解碰撞电离，这是一个基本过程，对于由这种材料制成的几乎任何实用设备的操作都至关重要，包括光电探测器，但也包括逻辑，存储器和传感晶体管。此外，该项目将有助于确定如何以类似于有关锗的文献报告的方式抑制黑磷中电子和空穴组合雪崩产生的过量噪声。这种学习最终可能导致突破性的，低成本的，多光谱通信和成像系统，与当前的解决方案相比，具有更高的速度和灵敏度。

项目成果

Black phosphorus avalanche photodetector

黑磷雪崩光电探测器

• DOI: 10.1109/drc.2017.7999500
• 发表时间: 2017
• 期刊: 75th Device Research Conference
• 作者: Atalla, Mahmoud R.;Koester, Steven J.
• 通讯作者: Koester, Steven J.