Characterization of Pristine and Functionalized Graphene on Metal Surfaces by Electron Spectroscopy

Graphene is a candidate material to replace silicon for the development of electronic devices with unsurpassed characteristics and of new carbon-based technologies. The success of graphene in this regard depends critically on three factors: first, a better understanding of the growth dynamics on substrate surfaces, notably metals, intended to achieve high-quality large grain size; second, functionalization or doping intended to open a tunable band gap in the otherwise zero-gap pristine graphene; and third, accurate monitoring of optical and electronic properties by spectroscopic investigation. Concerning the aforementioned interconnected aspects, this chapter focuses on current theoretical and experimental advances on the dynamics of graphene growth, and on the chemistry and morphology of functionalized graphene sheets. In particular, electron spectroscopy measurements (time-dependent x-ray photoelectron spectroscopy, angle-resolved photoemission spectroscopy, near-edge x-ray absorption fine structure) and ab initio calculations are used: (i) to follow graphene growth on metals starting from atomic and molecular scale to nanoscale; (ii) to study the interaction mechanisms between the growing graphene layer and the substrate; (iii) to investigate the effect of doping elements and adsorbates on the electronic structure of graphene. The last point represents a means (alternative to the use of graphene nanoribbons) to control the band gap, essential for the development of graphene- based electronics.