Graphene electronic sensors – review of recent developments and future challenges

Abstract

Electronic sensors based on graphene have a high potential in many applications, due to the unique properties of the graphene material. This study is a review where the authors discuss the properties of graphene which are useful to sensing applications and they report and describe different types of graphene electronic sensors: biological, mechanical, gas and chemical sensors. They also discuss the ways to functionalise graphene and the used device structures. They compare the performance of the main types of biological, mechanical and chemical sensors. Finally, they explain the future challenges of graphene-based sensors, in order to make graphene sensing systems and smart sensors, which would be their main breakthrough application. 1 Motivation and background After the award of the 2010 Nobel prize in Physics from 'groundbreaking experiments regarding the two-dimensional (2D) material graphene', there has been huge interest in using graphene for various applications including in electronics, photonics, displays, optoelectronics, photovoltaics, batteries and sensing. The significant amount of research work for the variety of applications is stimulated by graphene's exceptional material propertieselectrical, optical, thermal, mechanical and magnetic. Interested readers can consult [1-5] for an excellent introduction to graphene, its road map and what are some interesting applications of this amazing material. Graphene has several important properties including † Thinnest material making it suitable for flexible electronics, pressure sensors, electronic paper and so on. † Largest surface area per unit weight (∼2.7 × 10 3 m 2 /g) which is very important for sensing applications. † Excellent mechanical properties including being among the strongest material ever measured; extremely stiff and even stiffer than diamond; and very stretchable with up to ∼20% elasticity that are very important for sensors, flexible electronics and composites. † Record thermal conductivity that is higher than diamond for applications such as heat sinks to help alleviate thermal problems. † High current carrying capabilities, >10 2 higher than copper that makes it an exciting candidate for high-current density applications in nanoscale circuits. † Impermeable, for example, helium gas cannot get through which is important for nanofluidics and barriers. † Excellent electronic properties of very high intrinsic mobility; (>10 2 higher than silicon); charge carriers have zero rest mass; and long mean free path at room temperature on approximate millimetre range, properties that are critical for very high frequency electronics or terahertz imaging.

Sensing at the Surface of Graphene Field‐Effect Transistors

“…[65][66][67] The outcomes of researches in this area, however, did not reached the marked yet, [152] although ultimate single molecule sensitivity has been demonstrated and prototype biosensor chips in various forms have also been developed. [65][66][67] In the following sections, we will critically review the current trends in the development of GFET-based gas and ion sensors, protein and DNA sensors, and cellular sensors in revisiting the ambiguous cases and in meeting the social/scientific needs. A brief introduction to the graphene electrochemical sensors will also be given as their operation and sensing mechanism can be regarded to be complementary to GFET sensing technologies.…”

“…[171] One of the important expectations/outcomes of a highly sensitive and selective bioGFET is to analyze biomarkers for especially point-of-care applications. [65][66][67] As an example, femtomolars of prostate specific antigen/α1-antichymotrypsin (PSA-ACT) -a complex biomarker in prostate cancer diagnosis -could be detected using a rGO FET (Fig. 6c, lower panel) by functionalizing the graphene surface with PSA monoclonal antibody (PSAmAb) (Fig.…”

“…We expect these perspectives will prompt GFET's future development with potential to revolutionize the fields ranging from neuronal sensing to point-of-care medical diagnosis. [65][66][67]192] …”

“…[19,21] The fact that graphene possesses both superior mobility and noise performances, gives it a better signal-to-noise ratio (SNR) as advocated from time to time by literature, reporting graphene based biochemical sensors with superior performances compared to their Si based counterpart devices. [65][66][67][68] Figure 2b compares the noise performances of a GFET device supported by a SiO 2 /Si substrate and its counterpart after suspending the graphene monolayer by etching the underlying SiO 2 substrate (Figure 2a). [21] The large noise suppression was mainly attributed to the removal of any external trap states in the supported SiO 2 substrate since the 1/f noise in graphene devices is a surface phenomenon.…”

“…There has been a vast interest of industry, society, and scientific community in applying graphene materials for biochemical sensing applications, for portable point-of-care devices for remote diagnostics, for environmental monitoring, and even for DNA sequencing technologies, etc. [65][66][67] The outcomes of researches in this area, however, did not reach the market yet, [152] although ultimate single molecule sensitivity has been demonstrated and prototype biosensor chips in various forms have also been developed. [65][66][67] In the following sections, we will critically review the current trends in the development of GFET-based gas and ion sensors, protein and DNA sensors, and cellular sensors in revisiting the www.advmat.de Adv.…”