In situ chemical probing of hole defects and cracks in graphene at room temperature

Nanoscale ◽  
2018 ◽  
Vol 10 (23) ◽  
pp. 11052-11063 ◽  
Author(s):  
Ali I. Altan ◽  
Jian Chen

The vacancy defects in CVD-grown graphene can be visualized under SEM after the solid–gas phase reaction between H2S gas and exposed copper substrate in the air at room temperature.

2016 ◽  
Vol 273 ◽  
pp. 91-98 ◽  
Author(s):  
Jürgen Ulpts ◽  
Wolfgang Dreher ◽  
Lars Kiewidt ◽  
Miriam Schubert ◽  
Jorg Thöming

2016 ◽  
Vol 119 (1) ◽  
pp. 5-18
Author(s):  
Ádám Illés ◽  
Mária Farkas ◽  
Gábor László Zügner ◽  
Gyula Novodárszki ◽  
Magdolna Mihályi ◽  
...  

1993 ◽  
Vol 48 (12) ◽  
pp. 1234-1238 ◽  
Author(s):  
J. Nolte ◽  
J. Grußdorf ◽  
F. Temps ◽  
H. Gg. Wagner

Using the discharge flow method, the kinetics of the gas phase reactionHOCO + O2 products (1)was investigated at room temperature and pressures around p ≈ 2.0 mbar with Far Infrared LaserMagnetic Resonance (FIR-LMR) detection of HOCO, HO2 , and OH. From the measured concentration-versus-time decay profiles of HOCO in the absence and presence of a large excess of O2 , theoverall rate constant of the reaction was found to bek1 (296 K) = (9.9 ±1.5) • 1011 cm3/mol • s.The main reaction channel, which leads to production of HO2 + CO2 , could be established.


1997 ◽  
Vol 3 (S2) ◽  
pp. 401-402
Author(s):  
M. Yeadon ◽  
J.C. Yang ◽  
R.S. Averback ◽  
J.W. Bullard ◽  
D.L. Olynick ◽  
...  

The large surface area: volume ratios and fine grain size of nanophase materials give rise to novel and exciting structural and electrical properties that are of considerable scientific and technological interest. Using copper as a model system we have investigated the sintering of sputtered copper nanoparticles (4-20nm diameter) with a copper substrate in a novel UHV in-situ TEM.The nanoparticles were generated in a UHV chamber built into the side of the column by sputtering in 1.5Torr Ar. They were transported into the microscope in the gas phase and deposited on an electron transparent (001) copper foil mounted on a heated support. A typical bright-field (BF) image of the sample immediately after deposition at room temperature is shown in Fig. 1. The particles have assumed a random orientation on the substrate and remain stable for many hours at room temperature. The presence of both single particles and agglomerates of particles is evident in this image and examples are labelled ‘P’ and ‘A’, respectively


2002 ◽  
Vol 352 (3-4) ◽  
pp. 209-212 ◽  
Author(s):  
Yo-ichi Ishikawa ◽  
Yoshitaka Matsumoto

2015 ◽  
Vol 93 (1) ◽  
pp. 82-90 ◽  
Author(s):  
Rim Toukabri ◽  
Yujun Shi

The effect of source gas pressure on the gas-phase reaction chemistry of dimethylsilane (DMS) and monomethylsilane (MMS) in the hot-wire chemical vapor deposition process has been studied by examining the secondary gas-phase reaction products in a reactor using a soft laser ionization source coupled with mass spectrometry. For DMS, the increase in sample pressure has resulted in the formation of small hydrocarbons, including ethene, acetylene, propene, and propyne. This leads to a switch from silylene dominant chemistry to a free radical dominant one with the pressure increase at low filament temperatures of 1200 and 1300 °C. At the lower pressure of 0.12 Torr, the formation of 1,1,2,2-tetramethyldisilane by dimethylsilylene insertion reaction into the Si–H bond in DMS is favored over trimethylsilane produced from a free radical recombination reaction for a short reaction time. However, when the pressure is increased by 10 times, the gas-phase chemistry becomes dominated by the formation of trimethylsilane. We have demonstrated that trapping of the corresponding active intermediates by the small hydrocarbons produced in situ is responsible for the observed switch. In the study with MMS, the gas-phase chemistry is dominated by the formation of 1,2-dimethyldisilane and 1,3-disilacyclobutane at both pressures of 0.48 and 1.2 Torr. Unlike DMS, the gas-phase reaction chemistry with MMS does not involve free radicals, which are the precursors to produce small hydrocarbons. The absence of small hydrocarbons formed in situ with MMS explains the preservation in chemistry upon the increase in pressure when MMS is used as a source gas.


2006 ◽  
Vol 498 (1-2) ◽  
pp. 277-281 ◽  
Author(s):  
Gouji Asano ◽  
Tsukasa Satake ◽  
Kunio Ohtsuki ◽  
Hiroshi Funakubo

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