Nanocrystalline ruthenium oxide and ruthenium in sensing applications – an experimental and theoretical study
In this project, we have explored RuO2 and Ru nanoparticles (∼ ∼10 and ∼ ∼5 nm, respectively, estimated from XRD data) to be used as gate material in field effect sensor devices. The particles were synthesized by wet chemical procedure. The capacitance versus voltage characteristics of the studied capacitance shifts to a lower voltage while exposed to reducing gases. The main objectives are to improve the selectivity of the FET sensors by tailoring the dimension and surface chemistry of the nanoparticles and to improve the high temperature stability. The sensors were characterized using capacitance versus voltage measurements, at different frequencies, 500 Hz to 1 MHz, and temperatures at 100–400°C. The sensor response patterns have been found to depend on operating temperature. X-ray photoelectron spectroscopy (XPS) analyses were performed to investigate the oxidation state due to gas exposure. Quantum-chemical computations suggest that heterolytic dissociative adsorption is favored and preliminary computations regarding water formation from adsorbed hydrogen and oxygen was also performed.
Keywordsnanoparticles gas sensors RuO2 Ru FET devices
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This work was supported by grants from the Swedish Research Council, the Swedish Agency for Innovation Systems and Swedish Industry through the Center of Excellence, S-SENCE. We would like to thank Jeanette Nilsson for deposition of contact metals, and Evald Mild, at Linköping University, Sweden, who performed the skillful mounting of the sensor chips.
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