title: Investigating the CVD Synthesis of Graphene on Ge(100): toward Layer-by-Layer Growth.
abstract: Germanium is emerging as the substrate of choice for the growth of graphene in CMOS-compatible processes. For future application in next generation devices the accurate control over the properties of high-quality graphene synthesized on Ge surfaces, such as number of layers and domain size, is of paramount importance. Here we investigate the role of the process gas flows on the CVD growth of graphene on Ge(100). The quality and morphology of the deposited material is assessed by using μ-Raman spectroscopy, X-ray photoemission spectroscopy, scanning electron microscopy, and atomic force microscopy. We find that by simply varying the carbon precursor flow different growth regimes yielding to graphene nanoribbons, graphene monolayer, and graphene multilayer are established. We identify the growth conditions yielding to a layer-by-layer growth regime and report on the achievement of homogeneous monolayer graphene with an average intensity ratio of 2D and G bands in the Raman map larger than 3.
authors.affiliation: Dipartimento di Scienze, Università degli Studi Roma Tre , Viale Marconi 446, 00146 Rome, Italy.
authors.forename: A M
authors.initials: AM
authors.lastname: Scaparro
authors.affiliation: Center for Nanotechnology Innovation @NEST, Italian Institute of Technology , Piazza San Silvestro 12, 56127 Pisa, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Miseikis
authors.affiliation: Center for Nanotechnology Innovation @NEST, Italian Institute of Technology , Piazza San Silvestro 12, 56127 Pisa, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Coletti
authors.affiliation: Institute for Photonics and Nanotechnology, CNR , Via Cineto Romano 42, 00156 Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Notargiacomo
authors.affiliation: Institute for Photonics and Nanotechnology, CNR , Via Cineto Romano 42, 00156 Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Pea
authors.affiliation: Dipartimento di Scienze, Università degli Studi Roma Tre , Viale Marconi 446, 00146 Rome, Italy.
authors.forename: M
authors.initials: M
authors.lastname: De Seta
authors.affiliation: Dipartimento di Scienze, Università degli Studi Roma Tre , Viale Marconi 446, 00146 Rome, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Di Gaspare
keywords: Ge substrate; catalysis; chemical vapor deposition; graphene synthesis; single-layer graphene