AlGaN/GaN high electron mobility transistor (HEMT)-sensor with a catalytic Pt-gate is fabricated and tested for toxic H2S gas detection. AlGaN/GaN was chosen to extend the sensor detection range and to be able to operate at temperatures beyond those allowed by state-of-art Si-FET sensors. Testing was performed using a gas mixing apparatus in dry synthetic air ambient. High sensitivity, ΔI/I0, 8...

Of late, battery-driven high-performance gas sensors have gained acceptability in practical usage, whose atomic-scale structure has been revealed by μ-fluorescence X-ray absorption fine structure analysis. We studied the chemical distribution of Pd species in the Pd/Al2O3 catalyst overlayer in the real gas sensor at various degrees of deterioration. In a freshly prepared sensor, all Pd species ...

In this work we are presenting the implementation part of our research which explores two of the main Evolutionary Computation techniques which are; Genetic Algorithms (GAs) and Particle Swarm Optimization (PSO) to optimize the energy dissipation in a dynamic Wireless Sensor Network (WSN). We are evolving a hybrid algorithm by applying the GAs in the first phase to divide the sensor network int...

In this paper the voltage/current characteristics and the effect of NO2 gas on the electrical conductivity of a PbPc gas sensor array is studied. The gas sensor is manufactured using vacuum deposition of gold electrodes on sapphire substrate with the lead-phathalocyanine vacuum sublimed on the top of the gold electrodes. In a comparison between two versions of the PbPc gas sensor array, it was ...

This review focuses on polymer field-effect transistor (PFET) based gas sensor with polymer as the sensing layer, which interacts with gas analyte and thus induces the change of source-drain current (ΔISD). Dependent on the sensing layer which can be semiconducting polymer, dielectric layer or conducting polymer gate, the PFET sensors can be subdivided into three types. For each type of sensor,...

The use of catalytic gas sensors usually offers low selectivity, only based on their different sensitivities for various gases due to their different heats of reaction. Furthermore, the identification of the gas present is not possible, which leads to possible misinterpretation of the sensor signals. The use of micro-machined catalytic gas sensors offers great advantages regarding the response ...

Nanocrystalline thin film of Na0.1V2O5.nH2O xerogel obtained by sol gel synthesis was used as gas sensor. Gas sensing properties of different gases such as hydrogen, petroleum and humidity were investigated. Applying XRD and TEM the size of the nanocrystals is found to be 7.5 nm. SEM shows a highly porous structure with submicron meter-sized voids present throughout the sample. FTIR measurement...

We address the problem of detecting changes in the activity of a distant gas source from the response of an array of metal oxide (MOX) gas sensors deployed in an open sampling system. The main challenge is the turbulent nature of gas dispersion and the response dynamics of the sensors. We propose a change point detection approach and evaluate it on individual gas sensors in an experimental setu...

Multi-walled carbon nanotube (MWCNT) film has been fabricated onto Pt-patterned alumina substrates using the chemical vapor deposition method for NH(3) gas sensing applications. The MWCNT-based sensor is sensitive to NH(3) gas at room temperature. Nanoclusters of Co catalysts have been sputtered on the surface of the MWCNT film to enhance gas sensitivity with respect to unfunctionalized CNT fil...

Well-known cause of frequent failures of closed oxygen sensors is the appearance of gas bubbles in the electrolyte. The problem is traditionally associated with insufficient sealing of the sensor that is not always true. Study of a typical temperature regime of measurement system based on Clark sensor showed that spontaneous release of the gas phase is a natural effect caused by periodic warmin...