Equal variations of the Fermi level and work function in graphene at the nanoscale

Abstract

If surface effects are neglected, any change of the Fermi level in a semiconductor is expected to result in an equal and opposite change of the work function. However, this is in general not observed in three-dimensional semiconductors, because of Fermi level pinning at the surface. By combining Kelvin probe force microscopy and scanning tunneling spectroscopy on single layer graphene, we measure both the local work function and the charge carrier density. The one-to-one equivalence of changes in the Fermi level and the work function is demonstrated to accurately hold in single layer graphene down to the nanometer scale.

Exploitation of Bi2O2Se/graphene van der Waals heterojunction for creating efficient photodetectors and short‐channel field‐effect transistors

“…Firstly, as an optoelectronic or electronic device, its contact resistance is highly related to the eventual performance because the carrier transport is always limited by the high contact resistance. In this regard, Kelvin probe force microscope (KPFM) is utilized to measure the work function of the contact, by which the contact resistance between the graphene and 2D Bi 2 O 2 Se can be revealed . In Figures B and D Bi 2 O 2 Se is, respectively, bonded with the Au and the graphene electrode.…”

“…In this regard, Kelvin probe force microscope (KPFM) is utilized to measure the work function of the contact, by which the contact resistance between the graphene and 2D Bi 2 O 2 Se can be revealed. [17][18][19] In Figures 1B and 2D Bi 2 O 2 Se is, respectively, bonded with the Au and the graphene electrode. The work function interval between the graphene and Bi 2 O 2 Se is only 50 meV, which is visibly lower than that of the Au contact.…”

Free-Standing Graphene Oxide and Carbon Nanotube Hybrid Papers with Enhanced Electrical and Mechanical Performance and Their Synergy in Polymer Laminates

“…The local CPD is the potential of the GO/C-SWNT with respect to the tip apex. Therefore, in the absence of isolated charges and dipoles, CPD values represent the difference between the sample and the tip work function [ 54 ]. The presence of C-SWNT modifies the CPD between the tip and the GO surface as reported in Figure 4 d-h.…”

“…Table 1 shows the results of the best fits according to the following equation: where F , h , γ , α , E and ν are the total force (including adhesion), indentation depth, adhesion energy, tip apex conical angle, Young’s modulus and Poisson’s ratio, respectively. The details of the obtained equation are given in the Supplementary Material at Supplementary Information 1 (analysis of the nanoindentation curves), where we have adapted the results provided in Reference [ 54 ] to our tip geometry. The examples of the fit using Equation (2) for GO-paper, GO/C-SWNT and HOPG are given in Supplementary Material Figure S9 .…”

Effect of resonant impurity scattering of carriers on the Drude-peak broadening in uniaxially strained graphene

“…It was demonstrated in Ref. 34 that the work function varies in one-to-one correspondence to the position of the Fermi level in monolayer graphene. This relation was verified down to the nanometer scale, where due to inhomogeneities of the sample the local Dirac point also changes its position.…”