Advanced Graphene/Metal-Mesh Hybrid Transparent Electrodes via Ultraviolet (UV)–Ozone Treatment for UV-Range Optoelectronic Devices

The fabrication of advanced graphene/metal-mesh hybrid transparent electrodes (TEs) suitable for ultraviolet (UV)-range optoelectronic applications is reported herein, employing UV–ozone treatment. The UV–ozone treatment of transferred graphene is adopted to simultaneously enable oxidation doping and taint removal from the graphene surface and obtain the supplementary benefit of optical transmittance enhancement. Furthermore, the changes in the physical and chemical properties of graphene under different UV–ozone-treated times were characterized using Raman, X-ray/UV photoelectron spectroscopy, Hall measurements, and the transmission line method. Subsequently, hybrid structures combining various UV–ozone-treated graphene samples with a metal-mesh were tested as TEs in gallium nitride-based 375 nm near-UV light-emitting diodes (LEDs). Results indicate a noteworthy enhancement in light output power: a 48.3% increase relative to an untreated LED and an 18.3% increase compared to a conventional indium tin oxide (ITO)-based LED, particularly after 300 s of UV–ozone treatment. The present study provides a practical approach to overcome the limitations of existing ITO TEs for UV applications, thereby facilitating the future commercialization of graphene-based optoelectronic devices.