Researchers from Japan's Keio University and Waseda University explain that graphene has substantial potential for on-chip nanoscale light sources, due to its small size, high brightness and fast-modulating blackbody radiation sources, but a known problem is the need for transfer processes when mechanically exfoliated or chemical vapor deposited graphene are used, resulting in low productivity and degradation of graphene quality.
To address this issue, the team fabricated a graphene-based thermal light emitter by using an etching-precipitation method that does not require the transfer process. Infrared and visible light emission was observed from the central constricted area, forming a hot spot. Raman measurements confirmed that defect healing occurred in the central hot spot of graphene due to the annealing effect caused by Joule heating. The team also demonstrated that the device has long-term luminescence stability.
The scientists demonstrated thermal light emitters with the graphene directly grown on a quartz chip by the etching-precipitation method without the graphene transfer processes. These graphene light emitters exhibited bright, stable, and long-lifetime emissions in infrared (IR) and visible regions owing to the constricted graphene structure. It was demonstrated that the graphene light-emitter exhibited improved electrical conductivity under thermal emission, resulting from defect healing due to Joule heating, which contributed to the long lifetime of the device. Furthermore, a two-dimensional integrated graphene light emitter array was fabricated using homogeneous large-area multilayer graphene grown by the etching-precipitation method. This graphene light emitter array demonstrated high-speed switching and uniform IR emission.
These graphene-based light emitters can realize the integrated micro-emitter on a chip and so provide a promising avenue for the advancement of on-chip graphene light emitters.
