Introduction Of Graphene Layers Research Articles

High‐frequency modeling of Cu‐graphene heterogeneous interconnects

SummaryOne novel interconnect scheme consisting of both Cu and graphene sheet is proposed in this paper, with the advantages of both materials exploited greatly. It is shown that the introduction of graphene layers in such heterogeneous interconnect scheme can reduce its effective resistance and thereby improve its transmission performance. On the other hand, it is also demonstrated that both coated and double‐coated structures possess better electrical performance than that of the sandwich one at high frequencies, because the graphene is placed at the interconnect surface where current is crowded. With the help of Partial Element Equivalent Circuit method, together with equivalent circuit technique, the transmission characteristics of some Cu‐graphene interconnects are captured and compared with that of Cu wire, and the advantages of such heterogeneous interconnects can be enlarged with the advanced technology. Copyright © 2015 John Wiley & Sons, Ltd.

The effect of graphene layers on interfacial thermal resistance in composite nanochannels with flow

Interfacial thermal resistance $$R_{\mathrm{th}}$$ is analysed for a typical nanoscale interface with the help of nonequilibrium molecular dynamics. Liquid argon confined between two parallel copper walls is considered. Channel walls with varying wettabilities are modelled by depositing single and double layers of graphene on the copper nanochannel. To our knowledge, this is for the first time that such an attempt is made to modify the fluid–wall interaction strength in a more realistic manner and then to study its effect on thermal transport properties at the interface. Further, the variation of $$R_{\mathrm{th}}$$ at the solid–liquid interface in a nanoscale channel is studied in detail, while the liquid is made to flow through it. The simulation results reveal that the introduction of graphene layers on copper surface resulted in an enhancement of $$R_{\mathrm{th}}$$ . In order to analyse the molecular level mechanism resulting in the variation of $$R_{\mathrm{th}}$$ , vibrational density of states (VDOS) of the interfacial layer of wall atoms and the vibrational mobility of the adsorbed fluid layer were studied. A decrease in the vibrational mobility of fluid atoms was observed in nanochannels having graphene layers. Furthermore, in the case of composite nanochannels, we observe a decrease in the degree of overlap between the VDOS of the fluid atoms and the adjacent wall atoms. The variation of slip length with the Kapitza length is also investigated inside the composite nanochannels. Our results also suggest that the introduction of graphene layers could be a practical method for modifying $$R_{\mathrm{th}}$$ at nanochannel interfaces.

Grafting of self assembled polyaniline nanorods on reduced graphene oxide for nonlinear optical application

Polyaniline self assembled from nanorods synthesized by a novel inverse microemulsion polymerization technique, is covalently grafted to reduced graphene oxide layers. Amide linkages formed between polyaniline and reduced graphene oxide is confirmed with Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The formation mechanism of the cube-like nanostructures self assembled from nanorods, proposed is in good agreement with the experimental results. The cube-like morphology of polyaniline is disturbed during grafting due to the weakening of π–π stacking and H-bonding interactions between the nanorods by the introduction of graphene layers. Experimental results prove significant reduction and exfoliation of graphite oxide during grafting with polyaniline. At the same linear transmittance, the polyaniline–reduced graphene oxide hybrid (20cm/GW) shows increased nonlinear absorption coefficient compared to the individual components, namely polyaniline (9.5cm/GW) and graphite oxide (5.5cm/GW). The saturation intensity of the hybrid is also decreased considerably with respect to pristine polyaniline and GO. The hybrid with good nonlinear absorption coefficient and low limiting threshold opens up the way to use the material as a good optoelectronic material.

Lateral Photocurrent Scanning of Donor and Acceptor Polymers on Graphene Coated Substrates

Graphene provides a two-dimensional surface which can be utilized to interface with a variety of molecular species to modify opto-electronic processes. We use a scanning photocurrent technique to study the effect of graphene-coated anode substrates in semiconducting polymer device structures. The approach involves the measurement of the spatially varying photocurrent generated by an active semiconducting-polymer film sandwiched between a patterned substrate and a top electrode, where the narrow-incident light beam scans regions beyond the overlapping electrodes. We observe substantial difference in the spatial decay profile of the photocurrent upon introduction of graphene layers in the structure. Using simple circuit model and spreading impedance analysis we discuss the modification in carrier transport and recombination processes by underlying graphene layer in solar cell devices.