title: Gate dependent Raman spectroscopy of graphene on hexagonal boron nitride.
abstract: Raman spectroscopy, a fast and nondestructive imaging method, can be used to monitor the doping level in graphene devices. We fabricated chemical vapor deposition (CVD) grown graphene on atomically flat hexagonal boron nitride (hBN) flakes and SiO2 substrates. We compared their Raman response as a function of charge carrier density using an ion gel as a top gate. The G peak position, the 2D peak position, the 2D peak width and the ratio of the 2D peak area to the G peak area show a dependence on carrier density that differs for hBN compared to SiO2. Histograms of two-dimensional mapping are used to compare the fluctuations in the Raman peak properties between the two substrates. The hBN substrate has been found to produce fewer fluctuations at the same charge density owing to its atomically flat surface and reduced charged impurities.
authors.affiliation: Department of Physics, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Kanokporn
authors.initials: K
authors.lastname: Chattrakun
authors.forename: Shengqiang
authors.initials: S
authors.lastname: Huang
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: T
authors.initials: T
authors.lastname: Taniguchi
authors.forename: A
authors.initials: A
authors.lastname: Sandhu
authors.forename: B J
authors.initials: BJ
authors.lastname: LeRoy
mesh_terms: D001896:Boron Compounds / Q000737:chemistry*; D003460:Crystallization; D006108:Graphite / Q000737:chemistry*; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013499:Surface Properties
chemical_list: D001896:Boron Compounds; C017282:boron nitride; D012822:Silicon Dioxide; D006108:Graphite