School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing, 211189, China.
School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
Adv Mater. 2019 Oct;31(43):e1903829. doi: 10.1002/adma.201903829. Epub 2019 Sep 8.
Interfacial charge transfer is a fundamental and crucial process in photoelectric conversion. If charge transfer is not fast enough, carrier harvesting can compromise with competitive relaxation pathways, e.g., cooling, trapping, and recombination. Some of these processes can strongly affect the speed and efficiency of photoelectric conversion. In this work, it is elaborated that plasmon-induced hot-electron transfer (HET) from tungsten suboxide to graphene is a sufficiently fast process to prevent carrier cooling and trapping processes. A fast near-infrared detector empowered by HET is demonstrated, and the response time is three orders of magnitude faster than that based on common band-edge electron transfer. Moreover, HET can overcome the spectral limit of the bandgap of tungsten suboxide (≈2.8 eV) to extent the photoresponse to the communication band of 1550 nm (≈0.8 eV). These results indicate that plasmon-induced HET is a new strategy for implementation of efficient and high-speed photoelectric devices.
界面电荷转移是光电转换的一个基本且关键的过程。如果电荷转移不够快，载流子的收集可能会与竞争的弛豫途径（例如冷却、捕获和复合）相妥协。其中一些过程会强烈影响光电转换的速度和效率。在这项工作中，详细阐述了从氧化钨亚化物到石墨烯的等离子体诱导热电子转移（HET）是一个足够快的过程，可以防止载流子冷却和捕获过程。展示了一种由 HET 驱动的近红外探测器，其响应时间比基于常见的能带边缘电子转移的响应时间快三个数量级。此外，HET 可以克服氧化钨亚化物的能带隙（约 2.8 eV）的光谱限制，将光响应扩展到通信波段的 1550nm（约 0.8 eV）。这些结果表明，等离子体诱导的 HET 是实现高效和高速光电器件的一种新策略。
