Tuesday, February 19, 2013

1302.3976 (J. Campos-Delgado et al.)

Twisted bi-layer graphene: microscopic rainbows    [PDF]

J. Campos-Delgado, G. Algara-Siller, U. Kaiser, J. -P. Raskin
Twisted bi-layer graphene has recently attracted interest due to the peculiar electrical properties that arise from its random rotational configurations. Our experiments on CVD-grown graphene from Cu foil and transferred onto Si substrates, with an oxide layer of 100 nm, reveal naturally-produced bi-layer graphene patches which present different colorations when shined with white light. In particular, pink-, yellow- and blue- colored areas are evidenced. Combining optical microscopy, Raman spectroscopy and transmission electron microscopy we have been able to assign these colorations to ranges of rotational angles between the two graphene layers. Our results could lead the way to an easy selective identification of bi-layer graphene merely through the observation on an optical microscope.
View original: http://arxiv.org/abs/1302.3976

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