Making graphene visible on transparent dielectric substrates: Brewster angle imaging

Romagnoli P.; Rosa H.G.; Lopez-Cortes D.; Souza E.A.T.; Viana-Gomes J.C.; Margulis W.; De Matos C.J.S.

Making graphene visible on transparent dielectric substrates: Brewster angle imaging

Tipo

Artigo

Data de publicação

2015

Periódico

2D Materials

Citações (Scopus)

15

Autores

Romagnoli P.
Rosa H.G.
Lopez-Cortes D.
Souza E.A.T.
Viana-Gomes J.C.
Margulis W.
De Matos C.J.S.

Resumo

© 2015 IOP Publishing Ltd.The visibility of graphene is greatly increased by illuminating samples deposited on transparent dielectrics at the substrates' Brewster angle. Using a commercial ellipsometer, the reflectivity of monolayers of chemical vapour deposition (CVD) graphene is found to be up to 33 times higher than that of the substrate, i.e., an optical contrast as high as 3200% is obtained, more than 380 times higher than with standard optical microscopy. Also, with a simpler, homemade, experimental setup, a 1400% optical contrast was measured for a monolayer of CVD graphene and linear features as small as ~ 20 μmwere visible in a monolayer, while ~ 6 × 17 μm2 trilayers could still be imaged in exfoliated samples. It is also shown that the reflectance/transmittance ratio increases quadratically with the number of graphene layers, which may allow for counting layer numbers and identifying wrinkles and folds in transferred samples.

Assuntos Scopus

Brewster angle , Chemical vapour deposition , Dielectric substrates , Graphene layers , Linear feature , Optical contrast , Standard optical microscopy , Transparent substrate