Effect of subphase pH on Langmuir-Blodgett deposition of graphene oxide monolayers on Si and SiO 2 /Si substrates AIP Conf. Proc. 1512, 708 (2013); 10.1063/1.4791234 Reduced graphene oxide produced by rapid-heating reduction and its use in carbon-based field-effect transistors J. Appl. Phys. 112, 033701 (2012); 10.1063/1.4739486 High-yield dielectrophoretic assembly of two-dimensional graphene nanostructures Appl. Phys. Lett. 94, 053110 (2009);

Growth of high quality and monolayer graphene on copper thin films on silicon wafers is a promising approach to massive and direct graphene device fabrication in spite of the presence of potential dewetting issues in the copper film during graphene growth. Current work demonstrates roles of a nickel adhesion coupled with the copper film resulting in mitigation of dewetting problem as well as uniform monolayer graphene growth over 97 % coverage on films. The feasibility of monolayer graphene growth on Cu-Ni alloy films as thin as 150 nm in total is also demonstrated. During the graphene growth on Cu-Ni films, the nickel adhesion layer uniformly diffuses into the copper thin film resulting in a Cu-Ni alloy, helping to promote graphene nucleation and large area surface coverage. Furthermore, it was found that the use of extremely thin metal catalyst films also constraint the total amount of carbon that can be absorbed into the film during growth, which helps to eliminate adlayer formation and promote monolayer growth regardless of alloying content, thus improving the monolayer fraction of graphene coverage on the thinner films. These results suggest a path forward for the large scale integration of high quality, monolayer graphene into nanoelectronic and nanomechanical devices.

This paper presents graphene growth on Pt thin films deposited with four different adhesion layers: Ti, Cr, Ta, and Ni. During the graphene growth at 1000 °C using conventional chemical vapor deposition (CVD) method, these adhesion layers diffuse into and alloy with Pt layer resulting in graphene to grown on different alloys. This means that each different adhesion layers induce a different quality and number of layer(s) of graphene grown on the Pt thin film. This paper presents the feasibility of graphene growth on Pt thin films with various adhesion layers and the obstacles needed to overcome in order to enhance graphene transfer from Pt thin films. Therefore, this paper addresses one of the major difficulties of graphene growth and transfer to the implementation of graphene in nano/micro-electromechanical systems (NEMS/MEMS) devices.

This study presents chemical vapor deposition (CVD) growth of high-quality monolayer graphene on 100 nm-thick Pt thin films deposited on TiO2-coated silicon wafers. Conventional graphene growth on Pt thin films using CVD requires relatively thick films because of potential dewetting issues, which limits fabrication integration for nano-/microelectromechanical system (NEMS/MEMS) devices. Additional metal interlayers are commonly introduced to provide good adhesion between the Pt thin film and the substrate to achieve reliable graphene growth on thinner thin films. However, growing high-quality graphene on the Pt films with a thickness of less than 100 nm has still not been demonstrated because of dewetting issues. In this work, we introduce TiO2 as an adhesion layer for Pt on a Si substrate for graphene growth and show that using this adhesion layer, we are able to achieve large-area coverage of high-quality graphene without significant surface dewetting of a 100 nm Pt thin-film substrate. These results are confirmed by time-of-flight secondary ion mass spectrometry and Raman spectroscopy measurements. Our results show that graphene growth on Pt thin films can be more reliable using TiO2 as an adhesion layer and provides a guide for integration of growth of graphene onto the NEMS/MEMS device during the fabrication process.

Monolayer graphene is commonly grown on Cu substrates due to the self-limiting nature of graphene synthesis by chemical vapor deposition (CVD). Consequently, the growth of multilayer graphene by CVD has proven to be relatively difficult. This study demonstrates that the number of layers in graphene synthesized on a copper substrate can be precisely set by controlling the partial pressure of hydrogen gas used in the CVD process. This study also shows that a pressure threshold exists for a distinct transition from monolayer to multilayer graphene growth. This threshold is shown to be the boundary where the graphene growth process on Cu by CVD is no longer a self-limiting process. In addition, the multilayer graphene synthesized through the pressure control method forms in the Volmer-Weber mode with an AB stacking structure.Supplementary material for this article is available online