High-performance and high-sensitivity applications of graphene transistors with self-assembled monolayers

• Published in: Biosensors & bioelectronics Vol. 77; pp. 1008 - 1015
• Main Authors: Yeh, Chao-Hui, Kumar, Vinod, Moyano, David Ricardo, Wen, Shao-Hsuan, Parashar, Vyom, Hsiao, She-Hsin, Srivastava, Anchal, Saxena, Preeti S., Huang, Kun-Ping, Chang, Chien-Chung, Chiu, Po-Wen
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 15.03.2016
• Subjects: Antibodies, Monoclonal - chemistry; Arrays; Biomarkers, Tumor - analysis; Biosensing Techniques - instrumentation; Biosensors; Channels; Charge impurities; Chondroitin Sulfate Proteoglycans - analysis; Conductometry - instrumentation; Construction; Devices; Equipment Design; Equipment Failure Analysis; Field effect transistor; Graphene; Graphite - chemistry; Humans; Immunoassay - instrumentation; Membrane Proteins - analysis; Microchemistry - instrumentation; Neoplastic Cells, Circulating - chemistry; Obstacles; Reproducibility of Results; Self-assembled monolayers; Semiconductor devices; Sensitivity and Specificity; Transistors, Electronic; Field effect transistor; Self-assembled monolayers; Biosensors; Graphene; Charge impurities
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2015.10.078

Charge impurities and polar molecules on the surface of dielectric substrates has long been a critical obstacle to using graphene for its niche applications that involve graphene's high mobility and high sensitivity nature. Self-assembled monolayers (SAMs) have been found to effectively reduce the impact of long-range scatterings induced by the external charges. Yet, demonstrations of scalable device applications using the SAMs technique remains missing due to the difficulties in the device fabrication arising from the strong surface tension of the modified dielectric environment. Here, we use patterned SAM arrays to build graphene electronic devices with transport channels confined on the modified areas. For high-mobility applications, both rigid and flexible radio-frequency graphene field-effect transistors (G-FETs) were demonstrated, with extrinsic cutoff frequency and maximum oscillation frequency enhanced by a factor of ~2 on SiO2/Si substrates. For high sensitivity applications, G-FETs were functionalized by monoclonal antibodies specific to cancer biomarker chondroitin sulfate proteoglycan 4, enabling its detection at a concentration of 0.01fM, five orders of magnitude lower than that detectable by a conventional colorimetric assay. These devices can be very useful in the early diagnosis and monitoring of a malignant disease. •Patterned SAM arrays improve the field-effect transistor (FET) interface design.•Enhanced electrical performance is demonstrated in such designed graphene (G)-FETs.•Sub-femtomolar cancer biomarker detection is achievable with these G-FETs.