Quantification of coverage, uniformity and residues for CVD monolayer graphene transfer process based on image analysis.

[Display omitted] • Low-cost and industry-compatible MATLAB-based image analysis is employed to assess macroscopic coverage, uniformity and residues of graphene transferred onto Si/SiO 2 and ITO-covered glass substrates from optical microscopy images. • PMMA-, TRT- and PDMS-assisted transfer processes yield coverages exceeding 80 % on a Si/SiO 2 target substrate and are quantitatively compared using MATLAB-based image analysis of optical microscopy images of the transferred graphene. • Deeper insight into changes in fundamental properties of graphene induced by the transfer process itself is gained by detailed analysis of Raman spectra of pristine and transferred graphene. • MATLAB-based image analysis evaluation method for graphene transfer processes is validated by comparing the results obtained with it to Raman mapping results, both being in good agreement. The use of CVD-grown graphene requires a transfer method to transport this material from the metal foil on top of which it is grown onto a target substrate. In many cases this transfer changes its properties, leading to variations from one zone of the target substrate to another. Here we present a simple semi-automatic method for a quantitative study of the coverage, uniformity and residues of graphene transferred onto Si/SiO 2 substrates whose operation is not dependent on costly equipment, making it low-cost oriented. The method can be extrapolated to different target substrates, e.g., ITO-coated glass, and serves as an evaluation tool for graphene transfer processes. This is achieved by calculating a figure of merit, based on 2 proposed quantitative parameters (accounting for the coverage and the uniformity of the transferred graphene), while simultaneously determining the residues left by the transfer substrate using MATLAB-based image analysis of optical microscopy images. To corroborate the proposed method, a comparison between polydimethylsiloxane (PDMS), thermal release tape- (TRT) and polymethylmethacrylate- (PMMA) assisted transfer processes is performed, demonstrating that the methodology is valid for all cases. Coverages over 80 % are obtained, being in good agreement with results from the same transfer processes studied via Raman mapping. [ABSTRACT FROM AUTHOR]