Palladium (Pd) is well known for its capability to selectively detect hydrogen (H2) gas, where the detection process involves absorbing hydrogen gas molecules to form compound palladium hydrides. Such Pd-H interaction leads to the increase of electrical resistance and volume of Pd, simultaneously lowering its work function. These Pd-based hydrogen sensors would be more beneficial when connected to conventional semiconductor integrated circuits. Here, we utilize the Pd film as H-sensing electrode for metal/SiO2/p+-Si (MIM) capacitor, since we found the H-induced chain reactions in Pd/SiO2/p+-Si capacitor:Pd volume expansion, Pd-SiO2 contact are change, and the capacitance change. This capacitance change is connected to the gate of an electrically stable amorphous InGaZnO (a-IGZO) thin-film transistor (TFT). As a result, H-induced output as the drain current of a-IGZO TFT was statically and dynamically measured through the capacitance signal change from Pd-MIM sensor. This output current signal was converted to voltage when a load resistor was connected to the a-IGZO TFT in series. These sensor circuit configurations are regarded promising and novel because of their simplicity and practicality.
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© 2014 Elsevier B.V. All rights reserved.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Metals and Alloys
- Electrical and Electronic Engineering
- Materials Chemistry