Graphene Field‐Effect Transistor and Its Application for Electronic Sensing

Abstract

Graphene, because of its excellent mechanical, electrical, chemical, physical properties, sparked great interest to develop and extend its applications. Particularly, graphene based field-effect transistors (GFETs) present exciting and bright prospects for sensing applications due to their greatly higher sensitivity and stronger selectivity. This Review highlights a selection of important topics pertinent to GFETs and their application in electronic sensors. This article begins with a description of the fabrications and characterizations of GFETs, and then introduces the new developments in physical, chemical, and biological electronic detection using GFETs. Finally, several perspective and current challenges of GFETs development are presented, and some proposals are suggested for further development and exploration.

Sensing at the Surface of Graphene Field‐Effect Transistors

“…[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] Fig. 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 (Fig.…”

“…[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.…”

“…[8] It became clear later on that the large range of pH-induced gate shifts observed in the previous literature could be ascribed to defects as well as surface contaminations reflecting the quality of as-fabricated graphene. [66,183] Practically GFETs are normally composed of CVD graphene and contain therefore defects in the lattice introduced during growth. [55] Exfoliated samples are also subject to various polymer and metal contaminations coming from the fabrication process.…”

“…[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.…”

“…6c, upper panel). [78] Attomolar level detections have also been reported occasionally [205] but such significantly improved sensitivities were not always consistent with the more generally observed nM-pM detection limit, [66,67] suggesting that more dedicated efforts are still needed to improve the reliability and the reproducibility of the sensing response. [206] This brings us back to some of the fundamental issues associated with graphene-based BioFETs (and BioFETs in general) as eventually, after carefully designing and controlling every steps of a GFET, we will be looking at the Debye screening effects as an obstacle to achieve ultimate detection of a relatively large biomolecule in physiological conditions as previously discussed in Section 2.5 and will be further reviewed in the next Section 5.2.…”