Design and Analysis of Blue InGaN/GaN Plasmonic LED for High-Speed, High-Efficiency Optical Communications

We design, fabricate and analyze a nanostructured plasmonic light emitting diode (LED) that simultaneously increases modulation speed and radiative efficiency, compared to conventional LEDs and unpatterned plasmonic LEDs respectively. Our structure, optimized to ensure its integrability with electrical contacts, couples an InGaN/GaN blue LED with a Ag nanohole grating. Through spatiotemporally resolved photoluminescence measurements, we determine a 40-fold decrease in spontaneous emission lifetime, which sets an upper bound to the direct modulation bandwidth in the GHz regime. Additionally, through careful optimization of the plasmonic nanohole grating, we demonstrate a 10-fold increase in outcoupling efficiency relative to an LED with an unstructured plasmonic film. Our work bridges the plasmonic metamaterial and III-nitride semiconductor communities, laying the groundwork for high-speed, high-efficiency blue plasmonic LEDs for applications in visible light communication and beyond.