Graphene-based Composite Thin Films for Electronics

Abstract

The electrical properties of solution-processed composite thin films consisting of functionalized graphene sheets (FGS) as the filler and polystyrene (PS) as the host material are described. We demonstrate that transistors from graphene-based composite thin films exhibit ambipolar field effect characteristics, suggesting transport via percolation among FGS in the insulating PS matrix. Device characteristics as a function of the FGS size are also reported. The results indicate that devices fabricated using the largest size FGS yield the highest mobility values. This simple and scaleable fabrication scheme based on a commodity plastic could be useful for low-cost, macro-scale electronics.Graphene-based composites are emerging as new class of materials that hold promise for several applications. 1 Graphene, a single sheet of graphite, possesses extraordinary electrical, thermal, and mechanical properties arising from its unique structure. 2 When incorporated into polymer 3-6 or ceramic 7 matrices, these properties manifest as remarkable improvements in the host material. Graphene-based polymer composites exhibit extraordinarily low electrical percolation threshold (0.1 vol %) due to large conductivity and aspect ratio of the graphene sheets (atomic thickness and micrometersized lateral dimensions). 3,6 The mechanical and thermal properties of these materials rank among the best in comparison with other carbon-based composites due to strong interactions between polymer hosts and graphene sheets. 1,5 The highly conductive nature of graphene and ease of incorporation into polymers and ceramics has also opened up the possibility of their use as transparent conductors. 7 Furthermore, we recently demonstrated that atomically sharp edges of graphene incorporated into a PS host can be exploited for field emission. 8 Graphene is a zero band gap semiconductor exhibiting large electric field effect, 9 allowing doping with electrons or holes via electrostatic gating. The fact that graphene does not have a band gap poses a challenge for digital applications, but its high mobility is attractive for high frequency analog electronics or spintronics. 10,11 The semiconducting and robust mechanical properties of reduced graphene have been exploited for macro-scale thin film electronic devices 12,13 and high performance resonators. 14 Semiconducting behavior has yet to be demonstrated in graphene-based composites. The compatibility of graphene with polymers and ceramics opens up a route toward realization of semiconducting composite materials from electrically passive host materials. That is, introduction of percolating graphene network within an insulating material may render it semiconducting. In this study, we show that incorporation of functionalized graphene sheets (FGS) in polystyrene (PS) matrix results in composite thin films that are semiconducting and exhibit ambipolar field effect. These composites can be deposited uniformly over large areas in the form of thin films from solution onto which devices can be fabricate...

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Facile synthesis and application of Ag-chemically converted graphene nanocomposite

“…Due to its special physical and chemical properties, graphene has shown promise for several advanced technological applications, such as graphene-based composites, chemical detectors, fuel cells, and many others [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28].…”

Raman investigation of laser-induced structural defects of graphite oxide films

“…It is well known that graphene is characterised by properties of great potential: breaking strength (≈ 40 N/m), room temperature thermal conductivity (≈ 5000 W m -1 K -1 ), Young modulus (≈ 1 TPa) and so on [4]. Furthermore the electron mobility of graphene (1−2×10 5 cm 2 /Vs) is a hundred times higher than that of silicon [5], so graphene is a material of great potential for use in micro-electronics [6,7]. However the manufacture of integrated circuits needs a transfer printing method on small size of graphene films [8].…”