Bananakere Nanjegowda Chandrashekar1, Nianduo Cai1, Louis W Y Liu2, Ankanahalli Shankaregowda Smitha1, Zefei Wu2, Pengcheng Chen1, Run Shi3, Weijun Wang1, Jingwei Wang3, Chunmei Tang4, Chun Cheng5. 1. Department of Materials Science and Engineering and Shenzhen Key Laboratory of Nanoimprint Technology, Southern University of Science and Technology, Shenzhen 518055, PR China. 2. EEIT Department, Vietnamese German University, Le Lai Street, Hoa Phu Ward, Thu Dau Mot City, Binh Duong Province, Vietnam. 3. Department of Materials Science and Engineering and Shenzhen Key Laboratory of Nanoimprint Technology, Southern University of Science and Technology, Shenzhen 518055, PR China; Department of Physics, and Center for 1D/2D Quantum Materials, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China. 4. College of Science, Hohai University, Nanjing, Jiangsu 210098, PR China. 5. Department of Materials Science and Engineering and Shenzhen Key Laboratory of Nanoimprint Technology, Southern University of Science and Technology, Shenzhen 518055, PR China. Electronic address: chengc@sustech.edu.cn.
Abstract
HYPOTHESIS: Transfer of chemical-vapor-deposition (CVD) grown monolayer graphene from one substrate to another requires a transfer agent. The transfer agent usually needs to be removed by washing with organic solvent such as acetone or high temperature annealing, which is harmful to the structure integrity and intrinsic property of a graphene film. Here, we propose the use of camphor as a transfer agent to transfer monolayer graphene onto a target dielectric substrate, which bypasses these demanding steps and only needs the common alcohol solvent rinsing. EXPERIMENTS: To facilitate a crack-free graphene transfer, the proposed approach allows the camphor supported polycrystalline graphene to be rationally fastened with a thickened and solidified edge bead (i.e. camphor oil-filled boundary). A layer of camphor was first deposited onto a graphene/copper surface. The backside copper substrate was then etched away, whilst the camphor/graphene bilayer was placed onto a SiO2/Si substrate. Finally, the camphor remaining on the camphor/graphene/SiO2/Si sublimed into a vapor. The graphene/SiO2 stack was then examined by microscopic, spectral and electrical characterization. FINDINGS: The results of our examination suggest that the proposed method can guarantee a clean and damage-free graphene transfer. This method is particularly attractive in the application area for nano/micro-electronics, where it provides CVD-grown graphene the ability to be used on wide varieties of substrates that are sensitive to organic solvents and high temperature.
HYPOTHESIS: Transfer of chemical-vapor-deposition (CVD) grown monolayer graphene from one substrate to another requires a transfer agent. The transfer agent usually needs to be removed by washing with organic solvent such as acetone or high temperature annealing, which is harmful to the structure integrity and intrinsic property of a graphene film. Here, we propose the use of camphor as a transfer agent to transfer monolayer graphene onto a target dielectric substrate, which bypasses these demanding steps and only needs the common alcohol solvent rinsing. EXPERIMENTS: To facilitate a crack-free graphene transfer, the proposed approach allows the camphor supported polycrystalline graphene to be rationally fastened with a thickened and solidified edge bead (i.e. camphor oil-filled boundary). A layer of camphor was first deposited onto a graphene/copper surface. The backside copper substrate was then etched away, whilst the camphor/graphene bilayer was placed onto a SiO2/Si substrate. Finally, the camphor remaining on the camphor/graphene/SiO2/Si sublimed into a vapor. The graphene/SiO2 stack was then examined by microscopic, spectral and electrical characterization. FINDINGS: The results of our examination suggest that the proposed method can guarantee a clean and damage-free graphene transfer. This method is particularly attractive in the application area for nano/micro-electronics, where it provides CVD-grown graphene the ability to be used on wide varieties of substrates that are sensitive to organic solvents and high temperature.