Structural and Electronic Transport Properties of Fluorographene Directly Grown on Silicates for Possible Biosensor Applications

Abstract

Fluorographene (FG) ultrathin films are directly grown on flexible and nonflexible insulating silicate substrates and characterized in terms of their structural and electronic properties. FG is identified as an in-plane heterostructure consisting of sp 2 and sp 3 carbon domains. Solid-state 19 F NMR shows that fluorine is mainly localized in spaces adjacent to sp 2 carbon domains, which can be explained by a more uniform fluorine distribution in the boundaries between small sp 2 and sp 3 domains, rather than by an accumulation of fluorine in large sp 3 patches, and which is supported by Raman spectroscopy. The fluorine doping is further confirmed by spectroscopic ellipsometry studies, where it showed a band gap of 1.2 eV for thin-film FG, which is found to be consistent with density-functional-theory-based calculations for graphene layers doped with similar amounts of fluorine. Furthermore, this semiconducting FG layer grown with a large surface area has been identified as an ambipolar material from gate-controlled transport measurements, with holes being the majority of charge carriers. The transport properties of thin-film FG resemble those of reduced graphene oxide, another functionalized graphene derivative, with an Arrhenius-type temperature dependence of the resistance at high temperatures. This study opens up the possibilities of atomic-layer-based electronic circuitries and biosensors, where FG can be used as an active layer or dielectric support by tuning its fluorine content to the requisite level.

High Electrical Anisotropic Multilayered Self‐Assembled Organic Films Based on Graphene Oxide and PEDOT:PSS

“…[ 91–93 ] Thus, different doping agents or reduction processes need to be done on rGOs to enhance n‐type or p‐type transport. [ 91,94–98 ] For instance, Hwang et al. [ 11 ] showed that thermally reduced graphene oxide (TrGO) can behave as unipolar (p‐ or n‐type) or ambipolar transistor depending on the number of stacked layers on the semiconductor channel.…”

Ultrafast Charge Transfer Mechanism in Van der Waals Heterostructures of Topological Insulators with 2D Materials

“…It can be found that despite the explorations of different applications of vdW of 2D materials with TMs, there is limited or no report on their charge carrier and phonon dynamics, where such studies are vital in confirming the potential of such heterostructures in applications. − ,− ,− In the present study, the fabrication of vdW of bismuth telluride (Bi 2 Te 3 ), a well-known TM, with graphene, fluorographene, and molybdenum disulfide (MoS 2 ) atomic layers via a simple stacking of layers over a few layers of TM is achieved. These three different 2D systems are considered to form heterostructures with the TM and due to the difference in the parent properties of these layers, such as one is a semimetallic 2D system (graphene , ), the second one is a semiconducting defective 2D system (flurographene , ), and the third one is a 2D semiconductor with excitonic carriers (MoS 2 ). These three 2D systems have unique properties, such as, in graphene, the presence of fast electron transfer, reduced surface contamination, high spatial resolution, large surface area, fast response time, wide detection range, and high sensitivity due to their Dirac cone-related states .…”

Strain-Tunable Ultrastable MoS2/Fluorographene Hybrid Photodetectors of High Responsivity

“…Here, the strain-tunable photoresponsivity of such ultrastable FG-MoS 2 (FGMS) photodetectors is theoretically and experimentally demonstrated. The MoS 2 monolayer (MS) is grown over SiO 2 /Si using a chemical vapor deposition technique, while the FG films are grown directly on as-grown MoS 2 films, as reported before − (see Supporting Information). Though the chemical stability of such heterostructure-based photodetectors is proven by us, their mechanical robustness was not verified before.…”