Transition from Metallic to Semiconducting Behavior in Oxygen Plasma-treated Single-layer Graphene

2011 ◽  
Vol 1336 ◽  
Author(s):  
Amirhasan Nourbakhsh ◽  
Mirco Cantoro ◽  
Tom Vosch ◽  
Geoffrey Pourtois ◽  
Johan Hofkens ◽  
...  

ABSTRACTWe investigate the structural, optical and electrical properties of single-layer graphene exposed to oxygen plasma treatment. We find that the pristine semimetallic behavior of graphene disappears upon plasma treatment, in favour of the opening of a bandgap and the featuring of semiconducting properties. The metal-to-semiconductor transition observed appears to be dependent on the plasma treatment time. The semiconducting behavior is also confirmed by photoluminescence measurements. The opening of a bandgap in graphene is explained in terms of graphene surface functionalization with oxygen atoms, bonded as epoxy groups. Ab initio calculations of the density of states show more details about the oxygen–graphene interaction and its effects on the graphene optoelectronic properties, predicting no states near the Fermi level at increasing epoxy group density. The structural changes are also monitored by Raman spectroscopy, showing the progressive evolution of the sp2 character of pristine graphene to sp3, due to the lattice decoration with out-of-plane epoxy groups.

2011 ◽  
Vol 115 (33) ◽  
pp. 16619-16624 ◽  
Author(s):  
Amirhasan Nourbakhsh ◽  
Mirco Cantoro ◽  
Alexander V. Klekachev ◽  
Geoffrey Pourtois ◽  
Tom Vosch ◽  
...  

1995 ◽  
Vol 397 ◽  
Author(s):  
Jae-Ik Woo ◽  
Sang-Gul Lee ◽  
Dae-Gyu Moon ◽  
Chan-Hee Hong ◽  
Hoe-Sup Soh

ABSTRACTOxygen plasma treatment was performed on the excimer laser annealed poly-Si surface, followed by gate oxide deposition with low pressure chemical vapor deposition (LPCVD) in order to control the threshold voltage of excimer laser annealed poly-Si thin film transistors (TFTs).Threshold voltages of n-channel TFTs increase from 0.4 to 2.8 V by varying the treatment time from 0 to 7 min. It is shown the effective charge density increased toward negative direction with increase of the treatment time.In addition to the increase of threshold voltage, the oxygen plasma treatment on the Si surface led to an increase in the deposition rate of LPCVD oxide films with an apparent reduction of carbon around the interface between gate insulator and poly-Si film after oxygen plasma treatment.


2019 ◽  
Vol 6 (5) ◽  
pp. 055007 ◽  
Author(s):  
Anthony Akayeti ◽  
Weibing Zhang ◽  
Xiaohong Yan ◽  
Quan Wang

2008 ◽  
Vol 373-374 ◽  
pp. 430-433 ◽  
Author(s):  
Ping Chen ◽  
Jing Wang ◽  
Cheng Shuang Zhang ◽  
Chun Lu ◽  
Zhen Feng Ding ◽  
...  

Armos fiber (F-12 aramid fiber in paper) was provided with broad application foreground as reinforcement material for advanced composites in aviation and spaceflight field, due to its outstanding properties, such as high modulus, high strength, high temperature resistance, erosion resistance and so on. However, the exertion of property was still limited by slippery surface, low surface energy and weak interfacial adhesion performance. In this study, the effects of oxygen plasma treatment time on polar functional groups introduced onto the fiber surface, surface free energy and surface topographic images were discussed by X-ray photoelectron spectroscopy (XPS) analysis, dynamic contact angle analysis system (DCA) and atomic force microscopy (AFM), respectively. It was found that the content of oxygen element and polar functional groups on fiber surface were all increased obviously after oxygen plasma treatment. The content of oxygen element on surface for untreated F-12 aramid fiber was 11.13%, while it increased to 15.20% after oxygen plasma treatment for 10 min; The content of polar functional groups on surface for untreated F-12 aramid fiber was 28.14%, while it increased to 38.11% after oxygen plasma treatment for 10 min. The polar component (γp) of fiber surface energy increased sharply from 6.82 mN/m to 36.68 mN/m after 10 min plasma treatment, the total surface free energy was increased from 46.26 mN/m to 64.66 mN/m.The results indicated that oxygen plasma treatment had introduced a large amount of reactive functional groups onto the fiber surface, and these groups can form together as covalent bonding to improve the surface wettability and increase the surface energy of fibers. At the same time, oxygen plasma treatment was able to generate a mass of bulges and grooves on F-12 aramid fiber surface, which had an active effect on increasing the chemical bond and mechanical function between fiber and resin and enhancing the interfacial adhesion performance of composite. The fiber surface grooves had been increased with the time prolonging before 10 min while decreased after 10 min, the results maybe relate to partial organic on fiber surface melting. It had an adverse effect on the interfacial adhesion properties of composite. Therefore, the optimum plasma treatment time was between 5 min and 10 min.


Author(s):  
Mohd ‘Azizir-Rahim Mukri ◽  
Mohd Syafiq Elias ◽  
Madzlan Aziz ◽  
Masaki Tanemura ◽  
Mohd Zamri Mohd Yusop

A single graphene layer is superior many ways preferably in electronic devices application. However, mild modification of the graphene network could open a new potential to the ultrathin graphene membrane. Moreover, recent studies demonstrated that a few simple techniques could generate and control the nanopores size on single layer graphene sheet simultaneously. This review paper will discuss all potential techniques that are capable to generate nanopores structure on the pristine single layer graphene network.


2013 ◽  
Vol 781-784 ◽  
pp. 2605-2608 ◽  
Author(s):  
Wen Yu Wang ◽  
Xin Jin ◽  
Bo Wang ◽  
Li Na Bian

Ultra-high-molecular-weight polyethylene (UHMWPE) fibers were treated by low temperature oxygen-plasma. The effects of oxygen-plasma treatment time on the properties of UHMWPE have been investigated. The wetting ability and roughness were increased significantly after the treatment. While, the tensile strength at break of UHMWE fibers were decreased with the treatment time. The optimum plasma treatment time is 2min.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
E. C. Romani ◽  
D. G. Larrude ◽  
M. E. H. Maia da Costa ◽  
G. Mariotto ◽  
F. L. Freire

We synthesized single-layer graphene from a liquid precursor (triisopropyl borate) using a chemical vapor deposition. Optical microscopy, scanning electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy measurements were used for the characterization of the samples. We investigated the effects of the processing temperature and time, as well as the vapor pressure of the precursor. The B1s core-level XPS spectra revealed the presence of boron atoms incorporated into substitutional sites. This result, corroborated by the observed upshift of both G and 2D bands in the Raman spectra, suggests the p-doping of single-layer graphene for the samples prepared at 1000°C and pressures in the range of 75 to 25 mTorr of the precursor vapor. Our results show that, in optimum conditions for single-layer graphene growth, that is, 1000°C and 75 mTorr for 5 minutes, we obtained samples presenting the coexistence of pristine graphene with regions of boron-doped graphene.


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