Bottom‐Up Synthesized Nanoporous Graphene Transistors

Abstract

Nanoporous graphene (NPG) can exhibit a uniform electronic band gap and rationally-engineered emergent electronic properties, promising for electronic devices such as field-effect transistors (FETs), when synthesized with atomic precision. Bottom-up, on-surface synthetic approaches developed for graphene nanoribbons (GNRs) now provide the necessary atomic precision in NPG formation to access these desirable properties. However, the potential of bottom-up synthesized NPG for electronic devices has remained largely unexplored to date. Here, FETs based on bottom-up synthesized chevron-type NPG (C-NPG), consisting of ordered arrays of nanopores defined by laterally connected chevron GNRs, are demonstrated. C-NPG FETs show excellent switching performance with on-off ratios exceeding 10 4 , which are tightly linked to the structural quality of C-NPG. The devices operate as p-type transistors in the air, while n-type transport is observed when measured under vacuum, which is associated with reversible adsorption of gases or moisture. Theoretical analysis of charge transport in C-NPG is also performed through electronic structure and transport calculations, which reveal strong conductance anisotropy effects in C-NPG. The present study provides important insights into the design of high-performance graphene-based electronic devices where ballistic conductance and conduction anisotropy are achieved, which could be used in logic applications, and ultra-sensitive sensors for chemical or biological detection.

Growth Optimization and Device Integration of Narrow‐Bandgap Graphene Nanoribbons

“…The super-linearity of the I D -V D indicates the presence of a finite Schottky Barrier (SB) at the Pd-GNR interface, which is limiting the performance of the 5-AGNR devices, as also commonly reported for FETs made with other bottom-up synthesized GNRs. [21,49,51] The work-function engineering of the contact metal or doping of the contact area could potentially eliminate the SB effects. [52]…”

Nanoconfined synthesis of conjugated ladder polymers

“…A short-channel field-effect transistor (FET) device was fabricated using a chevron type 2D GNR, and exhibited excellent switching behavior with superior on-off ratios of 10 4 , in comparison with those of graphene. 131,132 Interestingly, the FET device exhibited n-type charge transport behavior under vacuum while the device in air converted to a p-type transistor. These device behavior changes are attributed to the absorption of gases or moisture that induced changes in the electronic band structures.…”

The effect of water on gold supported chiral graphene nanoribbons: rupture of conjugation by an alternating hydrogenation pattern

“…However, a detail slipped out of focus: most of the studies include the bulk (the graphene surface itself) and ignore the edges 15 which, in some cases, largely determine the properties of the carbon-based materials, as observed e.g. for porous graphene 16,17 or graphene nanoribbons (GNRs). 18–20 For this reason, we decided to test experimentally how GNRs interact with water.…”