G. Kaltenpoth, P. Schnabel, E. Menke
Aug 14, 2003
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Journal
Analytical Chemistry
Abstract
Palladium was electrodeposited onto lithographically patterned Si(100) “μ-channels” with dimensions of 2 μm (width) × 100 μm (length). The properties of these Pd-covered Si μ-channels for detecting dihydrogen gas were then evaluated. Pd electrodeposition was carried out under conditions favoring an instantaneous nucleation and growth mechanism. This strategy produced size-similar Pd particles at a coverage of (4−6) × 109 cm-2 within the confines of the Si μ-channel. When the mean particle radius, ro, was smaller than a critical value (ro < rc = 70−85 nm), each Pd particle was well separated on the surface from adjacent particles, on average, and no response to H2 gas attributable to the μ-channel was observed. As Pd particles were grown larger, to a mean radius of ro ≈ rc, adjacent particles on the surface touched and the electrical resistance of the μ-channel dropped by several orders of magnitude. These “type 2” H2 sensors exhibited a rapid (<1 s), reversible decrease in their resistance in response to ...