Enhanced Performance of Transparent Metal Mesh / Graphene Hybrid Film by UV-Ozone Treatment

Abstract

Indium Tin Oxide (ITO), which is the most widely used transparent electrode material, has a low sheet resistance and high transparency, however, it has a disadvantage of reducing transmittance in the ultraviolet (UV) region. To compensate for this weakness, graphene with high transmittance in the UV region and metal mesh with low sheet resistance were combined to produce a hybrid film. In this work, the UV-Ozone treatment was introduced to enhance the performance of the hybrid film by obtaining the graphene surface cleaning effect and graphene p-doping at the same time. The graphene oxidation process by UV-Ozone treatment was analyzed by Raman spectra and confirmed the p-doping of graphene is induced until 300 sec treatment. The existence of trade-off in optimum treatment time has been appeared by measuring sheet resistance and transmittance of graphene. In addition, Cr/Cu metal mesh was applied to treated graphene to observe the change in contact resistance and by analyzing graphene surface atomic force microscope (AFM) data, it has been confirmed that the graphene surface cleaning effect occurs up to 180 secs. Based on the results, Gallium Nitride (GaN)-based 450 nm blue LED was applied with UV-Ozone processed hybrid films, and it was established that devices performance was improved until 300 secs and then degraded again. The best performance of hybrid film with 300 secs UV-Ozone treatment has appeared similar to conventional ITO LED.