Comparative Study of Monolayer and Bilayer Epitaxial Graphene Field-Effect Transistors on SiC Substrates*Supported by the National Natural Science Foundation of China Under Grant PDF Download
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Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Abstract : Monolayer and bilayer graphenes have generated tremendous excitement as the potentially useful electronic materials due to their unique features. We report on monolayer and bilayer epitaxial graphene field-effect transistors (GFETs) fabricated on SiC substrates. Compared with monolayer GFETs, the bilayer GFETs exhibit a significant improvement in dc characteristics, including increasing current density IDS, improved transconductance g m, reduced sheet resistance R on, and current saturation. The improved electrical properties and tunable bandgap in the bilayer graphene lead to the excellent dc performance of the bilayer GFETs. Furthermore, the improved dc characteristics enhance a better rf performance for bilayer graphene devices, demonstrating that the quasi-free-standing bilayer graphene on SiC substrates has a great application potential for the future graphene-based electronics.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
Abstract : Monolayer and bilayer graphenes have generated tremendous excitement as the potentially useful electronic materials due to their unique features. We report on monolayer and bilayer epitaxial graphene field-effect transistors (GFETs) fabricated on SiC substrates. Compared with monolayer GFETs, the bilayer GFETs exhibit a significant improvement in dc characteristics, including increasing current density IDS, improved transconductance g m, reduced sheet resistance R on, and current saturation. The improved electrical properties and tunable bandgap in the bilayer graphene lead to the excellent dc performance of the bilayer GFETs. Furthermore, the improved dc characteristics enhance a better rf performance for bilayer graphene devices, demonstrating that the quasi-free-standing bilayer graphene on SiC substrates has a great application potential for the future graphene-based electronics.
Author: Hussain Ali Alsalman Publisher: ISBN: Category : Languages : en Pages : 131
Book Description
Graphene is a leading two dimensional (2D) material with good technological potential. Currently, it is being scaled up in synthesis methods in order to meet future demands in technology markets. In this dissertation, a study of transferred epitaxial graphene (TEG) as a synthesis method, for large area monolayer and AB stacked bilayer Graphene, is presented. Monolayer epitaxial graphene (EG) is grown on the (0001) face of silicon carbide (SiC) in an argon atmosphere at a temperature of 1600 o C. Bilayer graphene can thereafter be synthesized if needed by intercalating the monolayer in a 100% hydrogen flow at 1050 oC to release what is known as the "buffer layer" into another graphene layer forming a bilayer. Either form of graphene can subsequently be transferred off the SiC substrate to mitigate the negative effects of the substrate. We develop a transfer process based on a gold adhesion layer and demonstrate for the first time, the transfer of high quality monolayer transferred epitaxial graphene (MTEG) and AB stacked bilayer transferred epitaxial graphene (BTEG). We use Raman characterization methods to determine the number and quality of graphene layers as well as orientation for bilayers which was made possible by contrast enhancement upon substrate transfer. We report these characteristics for the first time. Extensive structural characterization that have never been done before and were made possible by the successful transfer procedure, are presented in the Transmission Electron Microscopy (TEM) section. We successfully show suspended MTEG and BTEG samples which was never shown in literature before. We fabricate Transmission Line Measurement (TLM) structures to study the quality of the contact resistance for MTEG and BTEG. We report values in the range of 600 [OMEGA].[MICRO SIGN]m for MTEG and 2400 [OMEGA].[MICRO SIGN]m for BTEG. We also fabricate Field Effect Transistors (FETs) to study the field effect mobility and carrier concentration of MTEG and BTEG. We report average room temperature field effect mobility values of around 1700 cm2/V.s with best value of 2800 cm2/V.s for MTEG. This is over two times gain in mobility before transfer and is competitive with current leading synthesis methods. We measured the room temperature field effect mobility of BTEG to be 250 cm2/V.s on average and with a best value of 335 cm2/V.s. To the knowledge of the author, there are no reports in literature on the measured mobility of BTEG. We carry out annealing studies at argon ambient of 300 oC for TEG and show unique properties for BTEG in which a demonstrated ten orders of magnitude, higher moisture absorption than MTEG is shown. A section in this dissertation will be dedicated to related work on chemical vapor deposition (CVD) hexagonal boron nitride (h-BN) which is a complimentary 2D material to graphene. Improvements on CVD growth by electropolishing the copper substrate will be demonstrated where root mean square (RMS) surface roughness of starting material is reduced from 177 nm to 12 nm, considerably improving subsequent h-BN CVD growth. A procedure for the transfer of CVD graphene onto CVD h-BN as well as fabrication of Van der Paw structures will be presented. We show initial results of improvements in mobility when CVD h-BN is used as a substrate for CVD graphene.
Author: Omar Azzaroni Publisher: John Wiley & Sons ISBN: 3527349901 Category : Technology & Engineering Languages : en Pages : 453
Book Description
Graphene Field-Effect Transistors In-depth resource on making and using graphene field effect transistors for point-of-care diagnostic devices Graphene Field-Effect Transistors focuses on the design, fabrication, characterization, and applications of graphene field effect transistors, summarizing the state-of-the-art in the field and putting forward new ideas regarding future research directions and potential applications. After a review of the unique electronic properties of graphene and the production of graphene and graphene oxide, the main part of the book is devoted to the fabrication of graphene field effect transistors and their sensing applications. Graphene Field-Effect Transistors includes information on: Electronic properties of graphene, production of graphene oxide and reduced graphene oxide, and graphene functionalization Fundamentals and fabrication of graphene field effect transistors, and nanomaterial/graphene nanostructure-based field-effect transistors Graphene field-effect transistors integrated with microfluidic platforms and flexible graphene field-effect transistors Graphene field-effect transistors for diagnostics applications, and DNA biosensors and immunosensors based on graphene field-effect transistors Graphene field-effect transistors for targeting cancer molecules, brain activity recording, bacterial detection, and detection of smell and taste Providing both fundamentals of the technology and an in-depth overview of using graphene field effect transistors for fabricating bioelectronic devices that can be applied for point-of-care diagnostics, Graphene Field-Effect Transistors is an essential reference for materials scientists, engineering scientists, laboratory medics, and biotechnologists.
Author: Günther G. Scherer Publisher: Springer Science & Business Media ISBN: 3540697551 Category : Technology & Engineering Languages : en Pages : 279
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Author: Hussain Ali Alsalman
Author: Omar Azzaroni
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Author: Günther G. Scherer