B/N co-doped graphene oxide gel with extremely-high mobility and ION/IOFF for large-area field effect transistors

Thin films of large-area graphene and graphene-based materials are highly desired for electrical applications. However, the current state-of-art synthesis methods produce large-area graphene films with multiple grain boundaries (GBs) that highly hinder their charge carrier mobilities and I_on/I_off ratios. Here, we demonstrate a femtosecond laser ablation process to produce B and N co-doped graphene oxide (GO) gels with controllable total doping percentage (between 0.8 at%-2.3 at%) and effectively reduced GBs concentration. The charge carrier mobilities and I_on/I_off ratios of the produced large-area gel (∼100 × 2400 μm²) field effect transistors (FETs) revealed extremely-high values of up to 9000 ± 3000 cm²/V and 9.7E+5, respectively, comparable to the state-of-art values of a single monolayer graphene nanoflake. The increased total doping percentage also proved to improve the chemical reactivity of the gels. This femtosecond laser ablation approach could prove effective for large-area FETs with controllable mobility, I_on/I_off ratio, and chemical reactivity.