Laterally extended atomically precise graphene nanoribbons with improved electrical conductivity for efficient gas sensing (original) (raw)
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Potential of Graphene nanoribbon (GNR) as a gas sensor is investigated in this work through a simulation based on semi empirical computations. The interactions between GNR (both pristine and defective) and three gas molecules (Ammonia, Mithane and Water) are deeply studied. A summary of some recent studies is presented so as to show that all GNRs, especially all sub-10 nm GNRs, exhibit semiconducting behavior with finite bandgap which is good to be used as a sensor. A sub-10 nm armchair-edged GNR is selected here to be used as sensing element for these three gases. All three gas molecules showed much stronger adsorption on the defective GNR than that on the pristine GNR. The change in density of state DOS diagram of pristine GNR before and after contacting gas molecules was found to be almost negligible near Fermi level. Change in GNR band feature due to donor type gas molecules was observed to be completely opposite of that for acceptor type gas molecules. The simulation result was...
Analysis of Simulated Output Characteristics of Gas Sensor Based on Graphene Nanoribbon
Journal of Nanomaterials, 2016
This work presents simulated output characteristics of gas sensor transistors based on graphene nanoribbon (GNRFET). The device studied in this work is a new generation of gas sensing devices, which are easy to use, ultracompact, ultrasensitive, and highly selective. We will explain how the exposure to the gas changes the conductivity of graphene nanoribbon. The equations of the GNRFET gas sensor model include the Poisson equation in the weak nonlocality approximation with proposed sensing parameters. As we have developed this model as a platform for a gas detection sensor, we will analyze the current-voltage characteristics after exposure of the GNRFET nanosensor device to NH3gas. A sensitivity of nearly 2.7% was indicated in our sensor device after exposure of 1 ppm of NH3. The given results make GNRFET the right candidate for use in gas sensing/measuring appliances. Thus, we will investigate the effect of the channel length on the ON- and OFF-current.
Recent advances in graphene based gas sensors
Graphene, a single, one-atom-thick sheet of carbon atoms arranged in a honeycomb lattice and thetwo-dimensional building block for carbon materials, has attracted great interest for a wide range ofapplications. Due to its superior properties such as thermo-electric conduction, surface area and mechan-ical strength, graphene materials have inspired huge interest in sensing of various chemical species. Inthis timely review, we discuss the recent advancement in the field of graphene based gas sensors withemphasis on the use of modified graphene materials. Further, insights of theoretical and experimentalaspects associated with such systems are also discussed with significance on the sensitivity and selectivityof graphene towards various gas molecules. The first section introduces graphene, its synthesis methodsand its physico-chemical properties. The second part focuses on the theoretical approaches that discussthe structural improvisations of graphene for its effective use as gas sensing materials. The third sectiondiscusses the applications of pristine and modified graphene materials in gas sensing applications. Vari-ous graphene modification methods are discussed including using dopants and defects, decoration withmetal/metal oxide nanoparticles, and functionalization with polymers. Finally, a discussion on the futurechallenges and perspectives of this enticing field of graphene sensors for gas detection is provided.
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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 se...
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