title: Influence of Substrate Microstructure on the Transport Properties of CVD-Graphene.
abstract: We report the study of electrical transport in few-layered CVD-graphene located on nanostructured surfaces in view of its potential application as a transparent contact to optoelectronic devices. Two specific surfaces with a different characteristic feature scale are analyzed: semiconductor micropyramids covered with SiO2 layer and opal structures composed of SiO2 nanospheres. Scanning tunneling microscopy (STM) and scanning electron microscopy (SEM), as well as Raman spectroscopy, have been used to determine graphene/substrate surface profile. The graphene transfer on the opal face centered cubic arrangement of spheres with a diameter of 230 nm leads to graphene corrugation (graphene partially reproduces the opal surface profile). This structure results in a reduction by more than 3 times of the graphene sheet conductivity compared to the conductivity of reference graphene located on a planar SiO2 surface but does not affect the contact resistance to graphene. The graphene transfer onto an organized array of micropyramids results in a graphene suspension. Unlike opal, the graphene suspension on pyramids leads to a reduction of both the contact resistance and the sheet resistance of graphene compared to resistance of the reference graphene/flat SiO2 sample. The sample annealing is favorable to improve the contact resistance to CVD-graphene; however, it leads to the increase of its sheet resistance.
authors.affiliation: Institut d'Electronique Fondamentale, UMR 8622 CNRS, University Paris Saclay , Orsay 91405, France.|Ioffe Institute , St. Petersburg 194021, Russia.|ITMO University , St. Petersburg 197101, Russia.
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Babichev
authors.affiliation: Peter the Great St. Petersburg Polytechnic University , St. Petersburg 195251, Russia.
authors.forename: Sergey A
authors.initials: SA
authors.lastname: Rykov
authors.affiliation: Institut d'Electronique Fondamentale, UMR 8622 CNRS, University Paris Saclay , Orsay 91405, France.
authors.forename: Maria
authors.initials: M
authors.lastname: Tchernycheva
authors.affiliation: Ioffe Institute , St. Petersburg 194021, Russia.
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Smirnov
authors.affiliation: Ioffe Institute , St. Petersburg 194021, Russia.
authors.forename: Valery Yu
authors.initials: VY
authors.lastname: Davydov
authors.affiliation: Ioffe Institute , St. Petersburg 194021, Russia.
authors.forename: Yurii A
authors.initials: YA
authors.lastname: Kumzerov
authors.affiliation: Ioffe Institute , St. Petersburg 194021, Russia.
authors.forename: Vladimir Y
authors.initials: VY
authors.lastname: Butko
keywords: CVD technique; TLM; contact resistance; graphene; interface; micropyramid LED