Structural and Electrical Investigation of C₆₀–Graphene Vertical Heterostructures

Abstract

Graphene, with its unique electronic and structural qualities, has become an important playground for studying adsorption and assembly of various materials including organic molecules. Moreover, organic/graphene vertical structures assembled by van der Waals interaction have potential for multifunctional device applications. Here, we investigate structural and electrical properties of vertical heterostructures composed of C60 thin film on graphene. The assembled film structure of C60 on graphene is investigated using transmission electron microscopy, which reveals a uniform morphology of C60 film on graphene with a grain size as large as 500 nm. The strong epitaxial relations between C60 crystal and graphene lattice directions are found, and van der Waals ab initio calculations support the observed phenomena. Moreover, using C60-graphene heterostructures, we fabricate vertical graphene transistors incorporating n-type organic semiconducting materials with an on/off ratio above 3 × 10(3). Our work demonstrates that graphene can serve as an excellent substrate for assembly of molecules, and attained organic/graphene heterostructures have great potential for electronics applications.

Optoelectronic Properties of Van Der Waals Hybrid Structures: Fullerenes on Graphene Nanoribbons

“…The most studied system has been the C${}_{60}$–graphene composite, in particular for applications in lithium batteries, electrodes for photovoltaics applications, supercapacitors, [7] and it has been studied in other fields such as organic thermoelectric materials [8]. Very recently, vertical heterostructures composed of C${}_{60}$ thin film on graphene have been assembled, and vertical graphene transistors were able to be fabricated [9]. …”

Growth of Large Crystalline Grains of Vanadyl‐Phthalocyanine without Epitaxy on Graphene

“…[ 41 ] CVD graphene provides the ideal TEM support to study molecular layers because it contributes virtually no contrast to images. Additionally, the organic molecules can be directly deposited onto graphene (as recently shown for the deposition of C 60 [ 42 ] and pentacene [ 43 ] ), which removes any degradation of the fi lm during the transfer process, or during focused ion beam lift-out preparation. [ 44 ] Here VOPc was deposited directly onto graphene coated TEM supports (see the Experimental Section for details).…”

Copper phthalocyanine based vertical organic field effect transistor with naturally patterned tin intermediate grid electrode

“…Additionally, Rossi et al [7] and Seidel et al [8] have shown that the intermediate electrode resistance can be minimized by using additional metallic or polymeric layers, respectively. There are also strategies to produce electrodes with controlled permeability like the use of sphere-lithography [15e17], co-deposition of metal and organic molecules [18], atomic layer deposition assisted nanoimprint lithography [19], random network of metallic nanowires [20], C 60 -graphene vertical heterostructures [21] or use of blockcopolymer templates [9] to obtain improved ON/OFF ratio and lower operation voltage. However, these strategies may require more complex device production steps, leading to a consequent cost rise and eliminating one of the potential advantages of the VOFETs.…”