Large-area nanopatterned graphene for ultrasensitive gas sensing

Cagliani, Alberto; Mackenzie, David; Tschammer, Lisa Katharina; Pizzocchero, Filippo; Almdal, Kristoffer; Bøggild, Peter

doi:10.1007/s12274-014-0435-x

Cited by 92 publications

(80 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This suggests that the dual-probe setup can detect the type (position of resonant level) and concentration (peak height) of adatoms on the surface of a graphene sample without the need of scanning the exact position of the impurity as required for a single-probe measurement. This is in line with the suggested applications of graphene as a gas sensor [58,59]. In the case of random vacancies we see an overall decrease in the transmission following the impurity concentration.…”

Section: B Configurational Averagesupporting

confidence: 89%

Dual-probe spectroscopic fingerprints of defects in graphene

et al. 2014

View full text Add to dashboard Cite

Recent advances in experimental techniques emphasize the usefulness of multiple scanning probe techniques when analyzing nanoscale samples. Here, we analyze theoretically dual-probe setups with probe separations in the nanometer range, i.e., in a regime where quantum coherence effects can be observed at low temperatures. In a dual-probe setup the electrons are injected at one probe and collected at the other. The measured conductance reflects the local transport properties on the nanoscale, thereby yielding information complementary to that obtained with a standard one-probe setup (the local density of states). In this work we develop a real-space Green's function method to compute the conductance. This requires an extension of the standard calculation schemes, which typically address a finite sample between the probes. In contrast, the developed method makes no assumption of the sample size (e.g., an extended graphene sheet). Applying this method, we study the transport anisotropies in pristine graphene sheets, and analyze the spectroscopic fingerprints arising from quantum interference around single-site defects, such as vacancies and adatoms. Furthermore, we demonstrate that the dual-probe setup is a useful tool for characterizing the electronic transport properties of extended defects or designed nanostructures. In particular, we show that nanoscale perforations, or antidots, in a graphene sheet display Fano-type resonances with a strong dependence on the edge geometry of the perforation.

show abstract

Section: B Configurational Averagesupporting

confidence: 89%

Dual-probe spectroscopic fingerprints of defects in graphene

et al. 2014

View full text Add to dashboard Cite

show abstract

“…The method allows us to study the perforation with no influence from periodic repetition or finite sample size. Additionally, the combination of recursive methods and a boundary self-energy allows for the investigation of antidot sizes realizable experimentally [3,62,71]. In fact, we consider both an example antidot with perfect edges and an exact structure found from high-resolution transmission electron microscope (TEM) images using pattern recognition [72,73].…”

Section: Vortex Currents Near Perforationsmentioning

confidence: 99%

Patched Green's function techniques for two-dimensional systems: Electronic behavior of bubbles and perforations in graphene

et al. 2015

View full text Add to dashboard Cite

We present a numerically efficient technique to evaluate the Green's function for extended two dimensional systems without relying on periodic boundary conditions. Different regions of interest, or 'patches', are connected using self energy terms which encode the information of the extended parts of the system. The calculation scheme uses a combination of analytic expressions for the Green's function of infinite pristine systems and an adaptive recursive Green's function technique for the patches. The method allows for an efficient calculation of both local electronic and transport properties, as well as the inclusion of multiple probes in arbitrary geometries embedded in extended samples. We apply the Patched Green's function method to evaluate the local densities of states and transmission properties of graphene systems with two kinds of deviations from the pristine structure: bubbles and perforations with characteristic dimensions of the order of 10-25 nm, i.e. including hundreds of thousands of atoms. The strain field induced by a bubble is treated beyond an effective Dirac model, and we demonstrate the existence of both Friedel-type oscillations arising from the edges of the bubble, as well as pseudo-Landau levels related to the pseudomagnetic field induced by the nonuniform strain. Secondly, we compute the transport properties of a large perforation with atomic positions extracted from a TEM image, and show that current vortices may form near the zigzag segments of the perforation.

show abstract

“…13,14 As the interaction with chemical species depends strongly on the presence of defects, nanopatterning has also been used to enhance the gas sensitivity. 6,7,15 Moreover, graphene nanopatterning offers the possibility of manipulating the absorption of visible and infrared light, 16 as well as plasmons. 17 For all these applications the critical pattern dimensions were in the sub-50 nm range, which imposes stringent requirements for the resolution of the patterning techniques to be used.…”

Section: Introductionmentioning

confidence: 99%

Defect/oxygen assisted direct write technique for nanopatterning graphene

et al. 2015

Self Cite

View full text Add to dashboard Cite

High resolution nanopatterning of graphene enables manipulation of electronic, optical and sensing properties of graphene. In this work we present a straightforward technique that does not require any lithographic mask to etch nanopatterns into graphene. The technique relies on the damaged graphene to be etched selectively in an oxygen rich environment with respect to non-damaged graphene. Sub-40 nm features were etched into graphene by selectively exposing it to a 100 keV electron beam and then etching the damaged areas away in a conventional oven. Raman spectroscopy was used to evaluate the extent of damage induced by the electron beam as well as the effects of the selective oxidative etching on the remaining graphene.

show abstract

Large-area nanopatterned graphene for ultrasensitive gas sensing

Cited by 92 publications

References 35 publications

Dual-probe spectroscopic fingerprints of defects in graphene

Dual-probe spectroscopic fingerprints of defects in graphene

Patched Green's function techniques for two-dimensional systems: Electronic behavior of bubbles and perforations in graphene

Defect/oxygen assisted direct write technique for nanopatterning graphene

Contact Info

Product

Resources

About