Voltage contrast X-ray photoelectron spectroscopy reveals graphene-substrate interaction in graphene devices fabricated on the C- and Si- faces of SiC

Abstract

A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements

Nanoscale Internal Fields in a Biased Graphene–Insulator–Semiconductor Structure

“…By exposing the dielectric surface to a constant flow of either electrons or X-rays, both positive and negative charging of a dielectric grown on a semiconductor were achieved. The experimentally determined photoemission intensities, including broadening and peak shifts, were modeled by making some basic assumptions regarding semiconductor band bending, potential profile across the oxide, and possible defects states in the film. − Cohen and co-workers have extended the application of flood gun charging strategies to a wider class of interfaces using the phrase “chemically resolved electrical measurements” to describe their method. − Suzer et al have performed extensive XPS-based measurements on defects and charging effects in oxides − and have also recently explored in-plane surface potential variations using XPS imaging on in-plane biased structures. − Lastly, Kobayashi et al, have applied a bias across a metal/oxide/semiconductor (MOS) stack using 3 nm Pt films as top electrodes and performed XPS in order to model the oxide defects density based on the evolution of the substrate band bending. − In all these studies, however, the determination of the potential profile across an entire stack was never performed.…”

AC-Modulated XPS Enables to Externally Control the Electrical Field Distributions on Metal Electrode/Ionic Liquid Devices

“…We have demonstrated that employing a DC bias during XPS data collection provides us with stable, steady-state information. 46 − 49 Furthermore, our research has emphasized the essential role of the AC excitation in examining dynamic evolution of the electrical potentials, as showcased in various of our publications. 50 − 54 Recently, we also reported on the use of Scanning Electron Microscopy (SEM) to detect similar changes caused by potential-induced intensity variations.…”

“…We have demonstrated that employing a DC bias during XPS data collection provides us with stable, steady-state information. − Furthermore, our research has emphasized the essential role of the AC excitation in examining dynamic evolution of the electrical potentials, as showcased in various of our publications. − Recently, we also reported on the use of Scanning Electron Microscopy (SEM) to detect similar changes caused by potential-induced intensity variations . Notably, these measurements have enabled us to observe the effects of time-resolved polarization and screening of metal electrodes into the liquid electrolyte surfaces over significant distances (centimeters) and extended time periods (hundreds of seconds), offering insightful chemical information.…”

Induced growth of quasi-free-standing graphene on SiC substrates

“…The S1 component is attributed to one-third of the carbon atoms in the buffer layer covalently bonded to the SiC substrate, and the S2 component results from the other two-thirds of the carbon atoms with the sp 2 conguration in the buffer layer. 23,24 Additionally, a minor contribution at high binding energy is attributable to the presence of C]O, 25,26 which might be formed during the process of graphitization, 25 or related to the sample preparation process during the XPS test.…”