Title :
A Pt/oriented-C hydrogen gas sensor
Author :
Moafi, A. ; Partridge, J.G. ; McCulloch, D.G. ; Sadek, A.Z. ; Kalantar-zadeh, K. ; Wlodarski, W.
Author_Institution :
Sch. of Appl. Sci., RMIT Univ., Melbourne, VIC, Australia
Abstract :
A Pt/C heterojunction has been fabricated and tested as a conductometric hydrogen gas sensor. The carbon layer, deposited between planar Au substrate contacts using a filtered cathodic vacuum arc (with an applied substrate bias of -500 V), consisted largely of vertically oriented graphitic sheets. These sheets have good through-film electrical conductivity and contributed to a low device resistance of ~60 ¿. The Pt layer (of 3 nm thickness) was deposited using a Gatan Model 682 Precision Electron Coating System (PECS). A change in the device resistance of >2% was exhibited upon exposure to 1% hydrogen gas (in synthetic, zero humidity air) at room temperature. The time for the sensor resistance to decrease by 2% under these conditions was 60 s and the baseline (zero hydrogen exposure) resistance remained constant to within 0.03% during and after the exposure tests.
Keywords :
carbon; electrical conductivity; electrical resistivity; gas sensors; hydrogen; metal-insulator boundaries; platinum; Au; Gatan Model 682 precision electron coating system; Pt-C; conductometric hydrogen gas sensor; filtered cathodic vacuum arc; heterojunction; low device resistance; size 3 nm; temperature 293 K to 298 K; through-film electrical conductivity; time 60 s; vertically oriented graphitic sheets; voltage -500 V; Conductivity; Contacts; Electric resistance; Electrons; Gas detectors; Gold; Heterojunctions; Hydrogen; Testing; Vacuum arcs;
Conference_Titel :
Sensors, 2009 IEEE
Conference_Location :
Christchurch
Print_ISBN :
978-1-4244-4548-6
Electronic_ISBN :
1930-0395
DOI :
10.1109/ICSENS.2009.5398166