Selectivity enhancement of metal oxide gas sensors using a micromachined gas chromatographic column

Zampolli, S.; Elmi, I.; Stürmann, J.; Nicoletti, S.; Dori, L.; Cardinali, G.C.

doi:10.1016/j.snb.2004.06.036

Cited by 131 publications

(77 citation statements)

References 7 publications

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“…This approach has been miniaturized with the goal to achieve sensor systems for nearly continuous monitoring operating in adsorption/desorption cycles. However, these systems today are typically based on closed pre-concentrators combined with micro-pumps leading to systems that are not low-cost [51,52]. We have developed a new approach based on open …”

Section: Novel Integrated Pre-concentrator Gas Sensor Microsystemmentioning

confidence: 99%

Highly Sensitive and Selective VOC Sensor Systems Based on Semiconductor Gas Sensors: How to?

et al. 2017

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Abstract:Monitoring of volatile organic compounds (VOCs) is of increasing importance in many application fields such as environmental monitoring, indoor air quality, industrial safety, fire detection, and health applications. The challenges in all of these applications are the wide variety and low concentrations of target molecules combined with the complex matrix containing many inorganic and organic interferents. This paper will give an overview over the application fields and address the requirements, pitfalls, and possible solutions for using low-cost sensor systems for VOC monitoring. The focus lies on highly sensitive metal oxide semiconductor gas sensors, which show very high sensitivity, but normally lack selectivity required for targeting relevant VOC monitoring applications. In addition to providing an overview of methods to increase the selectivity, especially virtual multisensors achieved with dynamic operation, and boost the sensitivity further via novel pro-concentrator concepts, we will also address the requirement for high-performance gas test systems, advanced solutions for operating and read-out electronic, and, finally, a cost-efficient factory and on-site calibration. The various methods will be primarily discussed in the context of requirements for monitoring of indoor air quality, but can equally be applied for environmental monitoring and other fields.

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Section: Novel Integrated Pre-concentrator Gas Sensor Microsystemmentioning

confidence: 99%

Highly Sensitive and Selective VOC Sensor Systems Based on Semiconductor Gas Sensors: How to?

et al. 2017

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“…The miniaturization of the chromatographic system is a prerequisite for many applications to ensure mobility and reduce system costs. The miniaturization of GC columns (µGC) (Sanchez et al, 2010;Zampolli et al, 2005) and additional building blocks like injectors and sampling units (Trzciński et al, 2017;Zampolli et al, 2007) has been investigated intensively and proven to be feasible. However, these systems are restricted in the choice of detectors compared to lab equipment.…”

Section: Introductionmentioning

confidence: 99%

“…The combination with metal oxide semiconductor (MOS) gas sensors also goes back many decades (Bârsan and Ionescu, 1994). MOS sensors are very sensitive (Zampolli et al, 2005), inexpensive and able to detect a broad range of gases. Recently, we have demonstrated that the sensitivity of MOS sensors can be increased significantly by a certain temperature cycled operation (TCO) mode (Baur et al, 2015) and that the quantity of gas can be derived directly from the sensor signal using a simple model for the surface reduction process (Schultealbert et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Novel method for the detection of short trace gas pulses with metal oxide semiconductor gas sensors

Baur

Schultealbert

Schütze

et al. 2018

J. Sens. Sens. Syst.

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Abstract.A novel method for the detection of short pulses of gas at very low concentrations, the differential surface reduction (DSR), is presented. DSR is related to the temperature pulsed reduction (TPR) method. In a high temperature phase, e.g., at 400 • C, the surface of a metal oxide semiconductor gas sensor (MOS) is oxidized in air and then cooled abruptly down to, e.g., 100 • C, conserving the large excess of negative surface charge. In this state reactions of reducing gases with surface oxygen are strongly favored, which increases the sensitivity. Due to the large energy barrier between metal oxide grains caused by the excess surface charge, a highly precise electrical measurement at very low conductance (down to 10 −11 S) is a prerequisite for this method. Moreover, the electrical measurement must be very fast to allow a good resolution of retention times. Applying the method to a doped SnO 2 detector, gas pulses down to a dosage of 1 ppb times seconds can be detected. The gas transport inside the detector is simulated using the finite element method (FEM) to optimize the gas transport and to keep response and recovery time as short as possible. With this approach, we have demonstrated a detection limit for ethanol of below 47 fg.

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“…The desirable characteristics of ideal humidity sensing materials should possess: good sensitivity over the entire range of humidity and temperature, stable chemical and physical property over time and thermal cycling, rapid response and recovery time, and low hysteresis [3]. Generally speaking, the humidity sensors are mainly fabricated by two kinds of materials: organic polymer films and porous ceramic films [4]. By comparison, ceramic humidity sensors are widely used than polymeric sensor due to the improved thermal, chemical and physics stability.…”

Section: Introductionmentioning

confidence: 99%

Effects of Surfactants on the Performance of ZrO2 Humidity Sensors

Wang¹,

Jie²,

Wang³

2017

Proceedings of the 7th International Conference on Education, Management, Information and Mechanical Engineering (EMIM 2017)

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Abstract. Nano-sized ZrO2 powders were synthesized by hydrothermal method with two types of surfactants (cetyltrimethyl ammonium bromide (cationic surfactant, CTAB), and sodium dodecylbenzene sulfonate (anionic surfactant, SDBS)). The phase structures and morphologies of the products were investigated by X-ray diffraction and scanning electron microscope. The sample with CTAB as surfactant (ZrO2-C) shows larger specific surface area and smaller particle size than ZrO2-S. The humidity sensor fabricated by ZrO2-C shows higher performance than the sample used SDBS as surfactant. The impedance of the ZrO2-C sensor decreases by about four orders of magnitude with relative humidity (RH) changed from 11 to 95%. The response and recovery time are 60 and 70 s, respectively. These results indicate that the performance of ZrO2 humidity sensors can be improved effectively by the addition of cationic surfactant.

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Selectivity enhancement of metal oxide gas sensors using a micromachined gas chromatographic column

Cited by 131 publications

References 7 publications

Highly Sensitive and Selective VOC Sensor Systems Based on Semiconductor Gas Sensors: How to?

Highly Sensitive and Selective VOC Sensor Systems Based on Semiconductor Gas Sensors: How to?

Novel method for the detection of short trace gas pulses with metal oxide semiconductor gas sensors

Effects of Surfactants on the Performance of ZrO2 Humidity Sensors

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