Study on factors impacting the fabrication of large-sized graphene single crystals in the quasi-sealed restricted growth chamber

Abstract

In this study, a quasi-sealed restricted growth chamber was designed to fabricate large-sized graphene single crystals by the low-pressure chemical vapor deposition (LPCVD) method. The results indicated that large-sized graphene single crystals were easier to be fabricated in the restricted growth chamber, which was about 6.8 times larger than that fabricated in the traditional growth chamber, indicating a higher growth rate of the graphene in the former. And the graphene nucleation density in the restricted growth chamber is lower than that in the traditional one. Meanwhile, graphene's nucleation density was further suppressed by using the oxide layer passivated copper substrates in the restricted growth chamber. With the help of the finite element numerical simulations and Newtonian fluid theory, the impacting mechanism of those two growth chambers on graphene nucleation and growth was also investigated. The results showed that the restricted chamber constructed a near-static growth environment for graphene, which not only significantly reduced the mass transfer rate of the carbon source above the substrate, but also helped prolong the residence time owing to the viscous force and the friction force.