BND-3M Medical Products 7 779 374 PT# 2360) with Ag/AgCl was used as the gate material. The measurement of the GFTEs was performed with Keysight B2902A.

Scaling up graphene fabrication is a critical step for realizing industrial applications of chemical vapor deposition (CVD) graphene, such as large-area flexible displays and solar cells. In this study, a roll-to-roll (R2R) graphene transfer system using mechanical peeling is proposed. No etching of graphene growth substrate is involved; thus, the process is economical and environmentally benign. A prototype R2R graphene transfer machine was developed. Experiments were conducted to test the effects of relevant process parameters, including linear film speed, separation angle, and the guiding roller diameter. The linear film speed was found to have the highest impact on the transferred graphene coverage, followed by the roller diameter, while the effect of separation angle was statistically insignificant. Furthermore, there was an interaction effect between the film speed and roller diameter, which can be attributed to the competing effects of tensile strain and strain rate. Overall, the experimental results showed that larger than 98% graphene coverage could be achieved with high linear film speed and large guiding roller diameter, demonstrating that a large-scale dry graphene transfer process is possible with R2R mechanical peeling.

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