State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, Zhejiang University, Hangzhou 310027, China.
Department of Physics and London Centre for Nanotechnology, King's College London, Strand, London WC2R 2LS, U.K.
Nano Lett. 2023 May 10;23(9):3731-3738. doi: 10.1021/acs.nanolett.2c04975. Epub 2023 Apr 25.
Ultrafast interfacing of electrical and optical signals at the nanoscale is highly desired for on-chip applications including optical interconnects and data processing devices. Here, we report electrically driven nanoscale optical sources based on metal-insulator-graphene tunnel junctions (MIG-TJs), featuring waveguided output with broadband spectral characteristics. Electrically driven inelastic tunneling in a MIG-TJ, realized by integrating a silver nanowire with graphene, provides broadband excitation of plasmonic modes in the junction with propagation lengths of several micrometers (∼10 times larger than that for metal-insulator-metal junctions), which therefore propagate toward the junction edge with low loss and couple to the nanowire waveguide with an efficiency of ∼70% (∼1000 times higher than that for metal-insulator-metal junctions). Alternatively, lateral coupling of the MIG-TJ to a semiconductor nanowire provides a platform for efficient outcoupling of electrically driven plasmonic signals to low-loss photonic waveguides, showing potential for applications at various integration levels.
在片上应用中，包括光互连和数据处理设备，人们非常希望在纳米尺度上实现电信号和光信号的超快速接口。在这里，我们报告了基于金属-绝缘体-石墨烯隧道结（MIG-TJ）的电驱动纳米级光学光源，其具有波导输出和宽带光谱特性。通过将银纳米线与石墨烯集成，在 MIG-TJ 中实现电致非弹性隧道，为结中的等离子体模式提供宽带激发，传播长度为数微米（比金属-绝缘体-金属结大 10 倍左右），因此以低损耗向结边缘传播，并与纳米线波导耦合，效率约为 70%（比金属-绝缘体-金属结高 1000 倍左右）。或者，MIG-TJ 与半导体纳米线的横向耦合为高效地将电驱动等离子体信号耦合到低损耗光子波导提供了一个平台，显示出在各种集成水平上应用的潜力。
