High on-off ratio graphene switch via electrical double layer gating

Abstract

This paper discusses the production and investigation of novel graphene switches by gating through an electrical double layer (EDL). Controlled voltage biases across a liquid dielectric and graphene induce electrochemical reactions within the dielectric and produce high electric fields in an EDL at the surface of graphene. As the electrochemical reactions occur within the dielectric, the EDL strength separates the electrochemically-produced ions based on their polarity, and provides the necessary molecular activation and deactivation energies to form weak, reversible molecular bonds between the produced ions and graphene. The reversible bonds between the ions and graphene are used to dynamically alter the electronic transport through graphene, which introduces an exciting assortment of device possibilities. Whereas traditional graphene devices are unuseful for electronic switches or digital logic due to an insufficient bandgap of graphene, the presented graphene electrochemical field-effect transistors (GEC-FETs) exhibit ON-OFF ratios larger than 10 4 with OFF-resistances as high as 10 M. Channel current, gate voltage, and dielectric medium are varied and compared to show their effect on device performance. The presented device and associated techniques show potential for integration in graphene digital-logic architectures.

Real-time label-free detection of DNA hybridization using a functionalized graphene field effect transistor: a theoretical study

“…Nowadays, nano filed effect transistor (FET) biosensors have attracted considerable attention (Bagherzadeh-Nobari et al 2018a , 2020 ; Kalantari-Nejad et al 2010 ) since they can be used as the label-free and real-time detection for biomolecules such as proteins, DNA, and bacteria (Thanihaichelvan et al 2021 ; Kalantari-Nejad et al 2010 ; Viswanathan et al 2015 ; Bagherzadeh-Nobari et al 2018b ; Wu et al 2018 ). Also, the fabrication of these FET biosensors is possible by some companies such as Graphenea (Fakih et al 2019 ; Hayashi et al 2020 ). In a FET DNA biosensor, the electrical properties of the FET such as source-drain current or conductance ( G ) of the channel change as a result of the attachment of complementary target DNA to the probe DNA immobilized on the channel surface.…”

Graphene Strain-Effect Transistor with Colossal ON/OFF Current Ratio Enabled by Reversible Nanocrack Formation in Metal Electrodes on Piezoelectric Substrates

“…For example, quantum confinement in graphene nanoribbons can lead to the opening of a finite bandgap, ,,, which can be translated into an ON/OFF current ratio of ∼10 3 in GFETs. , GFETs with high-k gate dielectrics such as ferroelectric barium titanate can also demonstrate ON/OFF current ratios of ∼10 4 . Electrochemical modification of the graphene channel through the use of electrolyte gating with honey, organic liquids, etc., can also lead to ON/OFF current ratios exceeding 10 8 in GFETs, albeit with limited yield and relatively poor endurance. , Finally, vertical heterostructure designs of graphene with other semiconducting materials (Si, Ge, WS 2 ) have reported ON/OFF current ratios as high as ∼10 6 . ,,, …”

“…17 Electrochemical modification of the graphene channel through the use of electrolyte gating with honey, organic liquids, etc., can also lead to ON/OFF current ratios exceeding 10 8 in GFETs, albeit with limited yield and relatively poor endurance. 20,21 Finally, vertical heterostructure designs of graphene with other semiconducting materials (Si, Ge, WS 2 ) have reported ON/ OFF current ratios as high as ∼10 6 . 18, 19,22,23 Here, we introduce a novel straintronic approach to achieve colossal ON/OFF current ratios (>10 7 ) in GFETs at room temperature without compromising the high transconductance offered by the graphene channel.…”