Abstract:

Graphene offers exceptional properties, such as ultra-high carrier mobility, near-ballistic transport characteristics, and ultra-high-frequency operational response, making it an ideal material for radio-frequency devices and high-speed optical communications. To realize its potential applications, high-quality graphene films must be integrated onto target substrates with reliability, uniformity, and scalability. Despite significant progress in the chemical vapor deposition of high-quality graphene on catalytic metal substrates, the transfer of such films onto application-targeted substrates remains necessary for large-scale technological use, but it faces challenges like contaminations and cracks. Graphene's flexibility and single-atom thickness make it vulnerable to damage and folding during the transfer process due to force disturbances and uneven force distribution. Traditional graphene transfer methods employ organic polymers as a medium and remove them using organic solvents after transferring graphene onto the desired substrates. However, this repetitive process generates organic waste and leaves unavoidable contamination due to the limited solubility of the polymer. Furthermore, selective interlacing of organic solvents during polymer removal can detach graphene from the substrate and cause cracks. In this study, we demonstrate a novel approach to address these issues. Instead of using organic polymers, we directly use the photoresist as the transfer medium to mechanically delaminate graphene from the metal growth substrate onto the targeted substrate. By doing so, we eliminate the need for repeated polymer coating on the graphene surface, enabling successful transfer without crack formation, wrinkles, or unintentional doping. The strong interaction between graphene and the photoresist, coupled with the weakened interaction between graphene and the growth substrate due to oxidation, ensures crack-free delamination. Moreover, the photoresist serves as a patterned mask plate for exposure, etching, and other subsequent device fabrication processes. As a result, the electrical properties of graphene are improved, achieving an average carrier mobility of 6200 cm²·V⁻¹·s⁻¹. This integrated approach not only enhances the device performance of two-dimensional materials but also paves the way for future applications of such materials in electronics and photonics. In conclusion, our method offers a promising solution for the successful transfer and device fabrication of graphene, enhancing its potential in the field of electronics and photonics.

Key words: Graphene transfer, Photoresist, Transfer medium, Carrier mobility