Method for electrostatic deposition of graphene on a substrate

A method for electrostatic deposition of graphene on a substrate comprises the steps of securing a graphite sample to a first electrode; electrically connecting the first electrode to a positive terminal of a power source; electrically connecting a second electrode to a ground terminal of the power source; placing the substrate over the second electrode; and using the power source to apply a voltage, such that graphene is removed from the graphite sample and deposited on the substrate

Electrostatic deposition of graphene in a gaseous environment: A deterministic route to synthesize rolled graphenes?

The synthesis of single-wall carbon nanotubes (SWCNTs) of desired diameters and chiralities is critical to the design of nanoscale electronic devices with desired properties.1-6 The existing methods are based on self-assembly, 7-16 therefore lacking the control over their diameters and chiralities. The present work reports a direct route to roll graphene. Specifically, we found that the electrostatic deposition of graphene yielded: (i) flat graphene layers under high vacuum (10-7 Torr), (ii) completely scrolled graphene under hydrogen atmosphere, (iii) partially scrolled graphene under nitrogen atmosphere, and (iv) no scrolling for helium atmospheres. Our study shows that the application of the electrostatic field facilitates the rolling of graphene sheets exposed to appropriate gases and allows the rolling of any size graphene. The technique proposed here, in conjunction with a technique that produces graphene nanoribbons (GNRs) of uniform widths, will have significant impact on the development of carbon nanotube based devices. Furthermore, the present technique may be applied to obtain tubes/scrolls of other layered materials

Charge transfer equilibria in ambient-exposed epitaxial graphene on (0001¯) 6 H-SiC

Article discussing research on charge transfer equilibria in ambient-exposed epitaxial graphene on (0001) 6 H-SiC

Charge transfer equilibria in ambient-exposed epitaxial graphene on (0001) 6 H-SiC

Article discussing research on charge transfer equilibria in ambient-exposed epitaxial graphene on (0001) 6 H-SiC

Morphological, Structural, and Chemical Effects in Response of Novel Carbide Derived Carbon Sensor to NH₃, N₂O, and Air

The response of two carbide derived carbons (CDCs) films to NH3, N2O, and room air is investigated by four probe resistance at room temperature and pressures up to 760 Torr. The two CDC films were synthesized at 600 (CDC-600) and 1000 °C (CDC-1000) to vary the carbon morphology from completely amorphous to more ordered, and determine the role of structure, surface area, and porosity on sensor response. Sensor response time followed kinetic diameter and indicated a more ordered carbon structure slowed response due to increased tortuosity caused by the formation of graphitic layers at the particle fringe. Steady state sensor response was greater for the less-ordered material, despite its decreased surface area, decreased micropore volume, and less favorable surface chemistry, suggesting carbon structure is a stronger predictor of sensor response than surface chemistry. The lack of correlation between adsorption of the probe gases and sensor response suggests chemical interaction (charge transfer) drive sensor response within the material; N2O response, in particular, did not follow simple adsorption behavior. Based on Raman and FTIR characterization, carbon morphology (disorder) appeared to be the determining factor in overall sensor response, likely due to increased charge transfer between gases and carbon defects of amorphous or disordered regions. The response of the amorphous CDC-600 film to NH3 was 45% without prior oxidation, showing amorphous CDCs have promise as chemical sensors without additional pretreatment common to other carbon sensors

Oriented nanomaterial air bridges formed from suspended polymer-composite nanofibers

Many recent nanomaterial device proposals and experimental studies call for the nanomaterial to be suspended as a two-point beam, or “air bridge”. This three-dimensional geometry simultaneously creates a nanomechanical element and isolates the element from various substrate effects (except at the supports), e.g., surface adhesion and strain forces, substrate temperature, reduced surface area in contact with the atmosphere, substrate conductivity, and parasitic capacitance. Not only are bridges accessible along the length of such structures, but nearfield probing, manipulation, and actuatio