title: Twisted bi-layer graphene: microscopic rainbows.
abstract: Blue, pink, and yellow colorations appear from twisted bi-layer graphene (tBLG) when transferred to a SiO2 /Si substrate (SiO2 = 100 nm-thick). Raman and electron microscope studies reveal that these colorations appear for twist angles in the 9-15° range. Optical contrast simulations confirm that the observed colorations are related to the angle-dependent electronic properties of tBLG combined with the reflection that results from the layered structure tBLG/100 nm-thick SiO2 /Si.
authors.affiliation: ICTEAM, Université catholique de Louvain, Louvain-la-Neuve, 1348, Belgium. jessica.campos@uclouvain.be.
authors.forename: J
authors.initials: J
authors.lastname: Campos-Delgado
authors.forename: G
authors.initials: G
authors.lastname: Algara-Siller
authors.forename: C N
authors.initials: CN
authors.lastname: Santos
authors.forename: U
authors.initials: U
authors.lastname: Kaiser
authors.forename: J-P
authors.initials: JP
authors.lastname: Raskin
keywords: HRTEM; Raman spectroscopy; graphene; optical contrasts; twisted bi-layer graphene