Impact of nitrogen doping on the band structure and the charge carrier scattering in monolayer graphene

Abstract

The addition of Nitrogen as a dopant in monolayer graphene is a flexible approach to tune the electronic properties of graphene as required for applications. Here, we investigate the impact of the doping process that adds N-dopants and defects on the key electronic properties, such as the mobility, the effective mass, the Berry phase and the scattering times of the charge carriers. Measurements at low temperatures and magnetic fields up to 9 T show a decrease of the mobility with increasing defect density due to elastic, short-range scattering. At low magnetic fields weak localization indicates an inelastic contribution depending on both defects and dopants. Analysis of the effective mass shows that the N-dopants decrease the slope of the linear bands, which are characteristic for the band structure of graphene around the Dirac point. The Berry phase, however, remains unaffected by the modifications induced through defects and dopants, showing that the overall band structure of the samples is still exhibiting the key properties as expected for Dirac fermions in graphene.

Doped graphene characterized via Raman spectroscopy and magneto-transport measurements

“…These results lead to an apparent contradiction with the co-doped sample showing a high MR and mobility, typically associated with pristine graphene 13,24 , while at the same time showing the largest intensities for the defect induced Raman D peak. This can be resolved by distinguishing defects, or localized neutral impurities, from dopants, which act as charged long range scattering regions.…”

“…The dopants were incorporated by adding different precursors during the growth phase: varying amounts of NH 3 for the N-doped and the in-house synthesized organic precursor ( B 2 N 2 Dibenzo[a,e]pentalenes (C 30 H 30 B 2 N 2 )) BNNB-DBP for the B,N-codoped sample. The transfer of the graphene from copper to Si/SiO 2 (p-doped Si covered with 300 nm SiO 2 ) followed a standard wet transfer protocol 13 . First, the graphene was covered with polymethylmethacrylate (PMMA), then the copper was etched by ammonium persulfate (3%).…”

Direct coupling-induced pseudoparity nonconservation scattering: bipolar spin diode and unipolar spin entanglement pairing

“…Experimentally, during the preparation process of graphene, there exist some structural defects on a substrate [66], which does not change the overall band structure of the samples, still exhibiting the key properties as expected for Dirac fermions in graphene [67]. However, the metallicity of the substrate can be used to control EPC and hence superconductivity [68].…”

Coexistence of Urbach‐Tail‐Like Localized States and Metallic Conduction Channels in Nitrogen‐Doped 3D Curved Graphene

“…While the electrical conductance and magnetoconductance of N-doped 3D graphene with 500-1000 nm pore radius (i.e., a relatively planer graphene) show the metallic behaviors, the variable range hopping behaviors are absent (Figures S3 and S13 and Section S5 in the Supporting Information), similar to the N-doped planar graphene grown by the high temperature CVD method. [23,26,27] Therefore, a large curvature of N-doped graphene honeycomb lattices appears to be an essential factor for the formation of the dual electronic state. For N-doped 3D graphene with a small pore size (i.e., large curvature), the mobility edges [59] can be formed around the Dirac point and the shifted DOS forms the Urbach-tail-like states [60] (Figure 2c).…”

“…[ 6–19 ] The enhanced electron scattering by N doping is mainly due to its atomically sharp electric potential. [ 20–26 ] The clustering of N dopants can effectively suppress the electron scattering and manipulates the electrical conductivity by carrier doping effects. [ 27 ] It has been theoretically and experimentally verified that N dopants occupying sublattices of graphene form a bandgap.…”