Toward efficient and tailorable mid-infrared emitters utilizing multilayer graphene

There is a continuing need for the development of cost-effective and sustainable mid-infrared light sources for applications such as gas sensing and infrared beacons. A natural replacement for the conventional incandescent sources still widely used in such applications is semiconductor LEDs, but to achieve emission at long wavelengths requires the realization of devices with narrow effective bandgaps, inherently leading to relatively poor internal and external quantum efficiencies. Recently, the technological potential of graphene-based incandescent emitters has been recognized, in part due to the ability of graphene to sustain extremely large current densities. Here, we introduce a simple architecture, consisting of a back-reflector behind a multilayer graphene filament, which we use to produce emitters with wall-plug-efficiencies comparable to state-of-the art semiconductor cascade LEDs. Coupled with the potential for high-speed modulation, resulting from the low thermal mass, our results demonstrate the feasibility of creating practicable infrared sources. (C) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).