Centimeter‐Scale High‐Resolution Metrology of Entire CVD‐Grown Graphene Sheets

Abstract

A high-throughput metrology method for measuring the thickness and uniformity of entire large-area chemical vapor deposition-grown graphene sheets on arbitrary substrates is demonstrated. This method utilizes the quenching of fluorescence by graphene via resonant energy transfer to increase the visibility of graphene on a glass substrate. Fluorescence quenching is visualized by spin-coating a solution of polymer mixed with fluorescent dye onto the graphene then viewing the sample under a fluorescence microscope. A large-area fluorescence montage image of the dyed graphene sample is collected and processed to identify the graphene and indicate the graphene layer thickness throughout the entire graphene sample. Using this metrology method, the effect of different transfer techniques on the quality of the graphene sheet is studied. It is shown that small-area characterization is insufficient to truly evaluate the effect of the transfer technique on the graphene sample. The results indicate that introducing a drop of acetone or liquid poly(methyl methacrylate) (PMMA) on top of the transfer PMMA layer before soaking the graphene sample in acetone improves the quality of the graphene dramatically over immediately soaking the graphene in acetone. This work introduces a new method for graphene quantification that can quickly and easily identify graphene layers in a large area on arbitrary substrates. This metrology technique is well suited for many industrial applications due to its repeatability and flexibility.

Pillared graphene and silicon nanocomposite architecture for anodes of lithium ion batteries

“…Raman spectra are shown to further confirm the quality of the as-grown pillar CNT and graphene nanostructure ( Figure 2). The presence of the G peak at 1583 cm -1 , the 2D peak at 2679 cm -1 and the G/2D ratio indicate the typical Raman characteristics for double layer graphene (DLG) sheets, which is similar to those reported for CVD grown graphene layers [13,[15][16][17]. Only a minor D band is observed at 1335 cm -1 which demonstrates the high quality of the as-grown structure (Figure 2, blue curve).…”

“…The PGN consists of pillar CNTs grown on top of a single/few-layer graphene film. Graphene layers (thickness <3 layers) in this work were grown by CVD at 950 o C using a mixture of CH 4 and H 2 as reported previously [4,8,12,13]. Next a thin layer of Fe catalyst was deposited onto the graphene covered copper substrate by electron beam evaporation.…”

Synthesis of Three Dimensional Carbon Nanostructure Foams for Supercapacitors

“…Raman spectra recorded from the graphene region locating with no CNTs coverage confirms the existence of graphene layers (Figure 2 bottom). The presence of the G peak at 1581 cm -1 , the G' peak at 2709 cm -1 and the G/G' ratio indicate the typical Raman characteristics for few-layer graphene (FLG) sheets, which is similar to those reported for CVD grown graphene layers [5]. No D band is observed at 1360 cm -1 due to the high quality of the as grown structure.…”

Graphene Metrology Using Fluorescence Quenching of Different Fluorescent Dyes

“…For industrial applications of graphene, a quick, repeatable and decisive metrology method must be developed to allow characterization of entire area or specific regions of interest of graphene sheets on glass or Si/SiO 2 substrates [5,6]. An alternative for high throughput large-scale characterization of graphene is fluorescent quenching microscopy (FQM) [5][6][7][8].…”

“…Furthermore, the imaging time in FQM is relatively shorter. Generally, a thin layer of fluorescent dye is coated on graphene and the energy is transferred from the dye molecules in excited state to graphene [5][6][7][8]. The energy transfer results in fluorescence quenching of the dye by graphene which depends on the thickness of the dye layer which determines the distance between graphene and dye molecules [9][10][11][12].…”