Browsing by Author "Ren, F."

Now showing 1 - 3 of 3

Effects of semiconductor processing chemicals on conductivity of graphene
(2012-07-01)
Chen, Chung Wei
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Ren, F.
;
Chi, Gou-Chung
;
Hung, S. C.
;
Huang, Y. P.
"Graphene layers on SiO2/Si substrates were exposed to chemicals or gases commonly used in semiconductor fabrication processes, including solvents (isopropanol, acetone), acids, bases (ammonium hydroxide), UV ozone, H2O, and O-2 plasmas. The recovery of the initial graphene properties after these exposures was monitored by measuring both the layer resistance and Raman 2D peak position as a function of time in air or vacuum. Solvents and UV ozone were found to have the least affect, while oxygen plasma exposure caused an increase of resistance of more than 3 orders of magnitude. Recovery is accelerated under vacuum but changes can persist for more than 5 h. Careful design of fabrication schemes involving graphene is necessary to minimize these interactions with common processing chemicals. (C) 2012 American Vacuum Society. [http://dx.doi.org/10.1116/1.4732517]"
Oxygen sensors made by monolayer graphene
(2012-01-01)
Hung, S. C.
;
Chen, C. W.
;
Yang, M. D.
;
Yeh, C. W.
;
Wu, C. H.
The electrical resistivity of monolayer graphene exhibit significant changes upon expose to different concentration of oxygen (O-2) at room temperature. The monolayer graphene, grown by chemical vapor deposition (CVD) with perfect uniformity within 1cmx1cm will attach O-2 molecules which will act as a p-type dopant and enhance the hole conductivity, make a change of resistivity of graphene thin film. We quantified the change of resistivity of graphene versus different O-2 concentration and the detection limit of the simple O-2 sensor was 1.25% in volume ratio.
Oxygen sensors made by monolayer graphene under room temperature
(2011-12-12)
Chen, C. W.
;
Hung, S. C.
;
Yang, M. D.
;
Yeh, C. W.
;
Wu, C. H.
The electrical resistivity of monolayer graphene exhibit significant changes upon expose to different concentration of oxygen (O(2)) at room temperature. The monolayer graphene, grown by chemical vapor deposition with perfect uniformity within 1 cm x 1 cm will attach O(2) molecules and enhance the hole conductivity, which will lead to a change of resistivity of graphene thin film. We quantified the change of resistivity of graphene versus different O(2) concentration and the detection limit of the simple O(2) sensor was 1.25% in volume ratio. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3668105]