Nitrogen-Doped Graphene: Efficient Growth, Structure, and Electronic Properties

Abstract

A novel strategy for efficient growth of nitrogen-doped graphene (N-graphene) on a large scale from s-triazine molecules is presented. The growth process has been unveiled in situ using time-dependent photoemission. It has been established that a postannealing of N-graphene after gold intercalation causes a conversion of the N environment from pyridinic to graphitic, allowing to obtain more than 80% of all embedded nitrogen in graphitic form, which is essential for the electron doping in graphene. A band gap, a doping level of 300 meV, and a charge-carrier concentration of ∼8×10(12) electrons per cm2, induced by 0.4 atom % of graphitic nitrogen, have been detected by angle-resolved photoemission spectroscopy, which offers great promise for implementation of this system in next generation electronic devices.

Electronic Structure Modification of Ion Implanted Graphene: The Spectroscopic Signatures of p- and n-Type Doping

“…[23][24][25][26] To add to the complexity of the situation, the synthesis conditions of doped graphene, which most commonly follow the chemical route, yield graphene samples of varying quality, 17 often with several types of dopant atom and defect configurations within the same specimen. [25][26][27] In a bid to produce uniformly6doped single6 layer graphene specimens, the successful implementation of low6energy ion implantation with either N or B was recently demonstrated, [28][29][30] achieving retention levels of the order of ~1% in good agreement with theoretical predictions. 31 This ion6implantation technique, commonly used by the modern semiconductor industry for doping Si wafers, for instance, has the advantage of allowing the uniform incorporation over a large area of single dopants on a pre6screened, single6layer, suspended graphene sample, and of producing comparatively few defects or ad6atom configurations.…”

Electron–Hole Symmetry Breaking in Charge Transport in Nitrogen-Doped Graphene

“…It is also seen that tuning N atomic concentration is accompanied by a change in the density of charged impurities. In order to quantitatively estimate the density of the charged impurities in our N-doped graphene samples, we use a Boltzmann kinetic theory, 20 considering charged impurity scattering in graphene, to fit our measured conductivity data. In the theory, the conductivity can be written as: 20…”

Inducing a Finite In-Plane Piezoelectricity in Graphene with Low Concentration of Inversion Symmetry-Breaking Defects

“…20 Apart from atom adsorption, other techniques can be used to break the inversion symmetry of graphene sheets, such as hole formation, 21 stacking control in graphene bilayers, 22 application of non-homogeneous strain, 23 and chemical doping. [24][25][26] Among these strategies, chemical doping seems the most promising as it already represents an effective experimental mean for tuning structural and electronic properties (such as band gap and work function) of graphene. 24,25,[27][28][29] Boron nitride (BN) chemical doping of graphene has recently been successfully achieved in different configurations and concentrations: semiconducting atomic layers of hybrid h-BN and graphene domains have been synthesized, 27 low-pressure chemical-vapor-deposition (CVD) synthesis of large-area few-layer BN doped graphene (BNG) has been presented, leading to BN concentrations as high as 10%; the BN content in BNG layers has been discussed to be related to the heating temperature of the precursor, as confirmed by X-ray photoelectron spectroscopy measurements.…”

“…[24][25][26] Among these strategies, chemical doping seems the most promising as it already represents an effective experimental mean for tuning structural and electronic properties (such as band gap and work function) of graphene. 24,25,[27][28][29] Boron nitride (BN) chemical doping of graphene has recently been successfully achieved in different configurations and concentrations: semiconducting atomic layers of hybrid h-BN and graphene domains have been synthesized, 27 low-pressure chemical-vapor-deposition (CVD) synthesis of large-area few-layer BN doped graphene (BNG) has been presented, leading to BN concentrations as high as 10%; the BN content in BNG layers has been discussed to be related to the heating temperature of the precursor, as confirmed by X-ray photoelectron spectroscopy measurements. 28 The synthesis of a quasi-freestanding BNG monolayer heterostructure, with preferred zigzag type boundary, on a weakly coupled Ir-surface has also been recently reported.…”