Wire-Based Core Field Effect Transistor (CoreFET) and Solid State Plasma Polymerization of Thiophene and Aniline Derivatives

During the last few years graphene has emerged as a potential candidate for electronics and optoelectronics applications due to its several salient features. Graphene is a smart material that responds to any physical change in its surrounding environment. Graphene has a very low intrinsic electronic noise and it can detect even a single gas molecule in its proximity. This property of graphene makes is a suitable and promising candidate to detect a large variety of organic/inorganic chemicals and gases. Typical solid state gas sensors usually requires high operating temperature and they cannot detect very low concentrations of gases efficiently due to intrinsic noise caused by thermal motion of charge carriers at high temperatures. They also have low resolution and stability issues of their constituent materials (such as electrolytes, electrodes, and sensing material itself) in harsh environments. It accelerates the need of development of robust, highly sensitive and efficient gas sensor with low operating temperature. Graphene and its derivatives could be a prospective replacement of these solid-state sensors due to their better electronic attributes for moderate temperature applications. The presence of extremely low intrinsic noise in graphene makes it highly suitable to detect a very low concentration of organic/inorganic compounds (even a single molecule ca be detected with graphene). In this article, we simulated a novel graphene nanoribbon based field effect transistor (FET) and used it to detect propane and butane gases. These are flammable household/industrial gases that must be detected to avoid serious accidents. The effects of atmospheric oxygen and humidity have also been studied by mixing oxygen and water molecules with desired target gases (propane and butane). The change in source-to-drain current of FET in the proximity of the target gases has been used as a detection signal. Our simulated FET device showed a noticeable change in density of states and IV-characteristics in the presence of target gas molecules. Nanoscale simulations of FET based gas sensor have been done in Quantumwise Atomistix Toolkit (ATK). ATK is a commercially available nanoscale semiconductor device simulator that is used to model a large variety of nanoscale devices. Our proposed device can be converted into a physical device to get a low cost and small sized integrated gas sensor.

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DNA hydrogel to improve solution-gate graphene field effect transistor in all-solid-state

Journal of Instrumentation ◽

10.1088/1748-0221/16/12/p12034 ◽

2021 ◽

Vol 16 (12) ◽

pp. P12034

Author(s):

S. Hu ◽

Y. Jia

Keyword(s):

Solid State ◽

Field Effect ◽

Field Effect Transistor ◽

Gate Dielectric ◽

Gate Dielectrics ◽

Hydrogel Scaffold ◽

Sensing Platform ◽

Graphene Field Effect Transistor ◽

Effect Transistor ◽

Dna Hydrogel

Abstract The solution-gate graphene field effect transistor (Sg-GFET), as a popular sensing platform, its applications are still hindered by the deficiency in all-solid-state, due to the dependence on liquid-state gate-dielectric. Inspired by DNA hydrogel which can provide microporous architecture to accommodate the fluidic analyte, moreover, its combination with graphene is believed to foster electron transport in the field of electrochemistry. We are interested to take advantage of DNA hydrogel's solid-state and capability for holding solution, and investigate whether it can replace the traditional solution. So pure DNA hydrogel, their complexes with GO (GO/DNA hydrogel) and RGO (RGO/DNA hydrogel) are studied herein. Their micro-porous 3D morphologies are demonstrated, their influences on the electrical characteristics of GFETs are carefully examined and proved to be able to maintain the typical bipolarity of Sg-GFET, firstly. Then, pure DNA hydrogel and GO/DNA hydrogel are selected as the optimized gate-dielectrics, because of their renewability after dehydration. Furthermore, by using aptamer-based heavy metal ions (Pb2+ and Hg2+) detections as proof-of-concept, the strategies for building the sensing platform based on the optimized hydrogel dielectric-gated GFETs are studied. It is found, for the purpose of substituting fluidic dielectric in traditional Sg-GFET, the scheme of directly mounting aptamer on graphene channel and coating pure DNA hydrogel on it is demonstrated to be better than the strategies of using GO/DNA hydrogel and hybriding aptamer probes in hydrogel scaﬀold. It is explained according to surface charge sensing mechanism. At last, the performances of the sensing platform based on the proposed DNA hydrogel gated GFETs are testified by the detections and selectivity examinations for Pb2+ and Hg2+. Conclusively, pure DNA hydrogel is expected to be a promising candidate in the future all-solid-state Sg-GFET.

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