Top-Down versus Bottom-Up Fabrication of Graphene-Based Electronics

Abstract

Graphene electronic devices can be made by top-down (TD) or bottom-up (BU) approaches. This Perspective defines and explains those two approaches and discusses the advantages and limitations of each, particularly in the context of graphene fabrication. It is further exemplified using graphene nanoribbons as the prototypical graphene structure that can be prepared using either a TD or BU approach. The TD approach is well-suited for placement of large arrays of devices on a chip using standard patterning tools. However, the TD approach severely compromises the edges of the graphene since present fabrication tools are coarse relative to the ∼0.1 nm definition of a C−C bond. The BU approach can afford exquisite control of the graphene edges; however, placing the structures, en mass, in the locations of interest is often impossible. Also, using the BU approach, it can be very difficult to make device structures long enough for integration with TDderived probe electrodes. Specific examples are shown, along with an outlook for optimization of future graphene devices in order to capitalize upon the advantages of both TD and BU fabrication methodologies.

Molecular dynamics simulation study of a carbon-nanotube oscillator in a graphene-nanoribbon trench

“…However, although the current CNT oscillator in GNR trench is difficult to implement by simple processes, we should note that such a structure can be achieved by the nanotube-graphene hybrid nanofabrication processes, as discussed in the Introduction [40][41][42][43][44][45][46][47][48].…”

“…Quite recently, fullerene-graphene hybrids have been experimentally produced and theoretically investigated [34][35][36][37][38][39]. In particular, nanotube-graphene hybrid also has great potential application [40][41][42][43][44][45][46][47][48]. Theoretical work suggested that a covalently bonded graphene-nanotube hybrid material would extend those properties to three dimensions, and be useful in energy storage and nanoelectronic technologies [40].…”

Carbon Electrodes in Molecular Electronics

“…Some of these include the need to create a band gap (as discussed earlier), which limits its applications in high-performance integrated logic circuits and the contact resistance between graphene and other electrode materials. For these reasons, it has been suggested that the controlled integration of graphene layers into circuits using a top-down, bottom-up, or hybrid approach [115] is likely to appear after 2020 [95].…”

Synthesis and characterization of graphene sheets grafted with linear triblock copolymers based on methacrylate ester

“…Likewise, graphene sheets (GSs) had received various attentions in efforts to develop high-performance functional materials [3], mainly including transistors, photovoltaic electrodes, resonators, and ultracapacitors [4][5][6]. There were two typical approaches that had been employed to synthesize GS materials [7]. The ''bottom-up'' approach allowed tuning of the fine structure of GSs, such as shape, size, and location of defects [7,8].…”

“…There were two typical approaches that had been employed to synthesize GS materials [7]. The ''bottom-up'' approach allowed tuning of the fine structure of GSs, such as shape, size, and location of defects [7,8]. This approach had established a basis for bandgap control, supramolecular assembly, and device applications of GSs.…”