Metal oxide semiconductor gas sensors in environmental monitoring

Binions, Russell; Naik, Anupriya J. T.

doi:10.1533/9780857098665.4.433

Cited by 50 publications

(25 citation statements)

References 97 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…There are two types of MOS sensors, the n-type, where there are more electrons than protons, and the p-type, where the number of electrons is inferior, and the electricity flows through the positive holes. The n-type sensor have the internal resistance decreased by reducing gases, and increased by the oxidizing gases, whereas the p-type presents the opposite effect [28,122,123]. The use of UV light within the sensing element allows a lower sensing temperature, produces lower internal resistance, as electrons are inducted to pair, and the resistance of the sensing material will increase, proportionally to the increase of the target gas [29].…”

Section: Metal Oxide Semiconductorsmentioning

confidence: 99%

IoT-Enabled Gas Sensors: Technologies, Applications, and Opportunities

Gomes

Rodrigues

Rabêlo

et al. 2019

JSAN

View full text Add to dashboard Cite

Ambient gas detection and measurement had become essential in diverse fields and applications, from preventing accidents, avoiding equipment malfunction, to air pollution warnings and granting the correct gas mixture to patients in hospitals. Gas leakage can reach large proportions, affecting entire neighborhoods or even cities, causing enormous environmental impacts. This paper elaborates on a deep review of the state of the art on gas-sensing technologies, analyzing the opportunities and main characteristics of the transducers, as well as towards their integration through the Internet of Things (IoT) paradigm. This should ease the information collecting and sharing processes, granting better experiences to users, and avoiding major losses and expenses. The most promising wireless-based solutions for ambient gas monitoring are analyzed and discussed, open research topics are identified, and lessons learned are shared to conclude the study.Technologies to sense gases and wireless communications support are elaborated in Sections 5 and 6, respectively. The most promising solutions in terms of sensing methods and IoT-enabled solutions are discussed in Section 7 and open research topics are identified. Lessons learned are shared at Section 8 and, finally, Section 9 concludes the study. Background on Environmental GasesSome gases are the key to ensure the functionality of systems and entire industries, as well as the presence of other gases being a problem in other fields, causing the loss of entire production lines, as in the food industry, or even cause the loss of lives and explosions. In this section, the most important gases in terms of pollution monitoring and control, health issues, and accident prevention are listed with their main characteristics.Oxygen (O 2 ) is the most important gas for life, and is crucial in numerous fields. Patients under anesthesia, or recovering from surgery and from certain diseases need controlled O 2 doses to keep them alive and fully recovered. The decrease of oxygen levels in enclosed spaces can be related with other gases leakage, which would lead people inside these spaces to asphyxiate, leading to an unconscious state, or even to death [29]. Numerous industrial processes rely on the correct concentration of this gas to achieve the best results, mainly chemical and combustion, which without the correct percentages will not grant the best performance of systems. Engine control systems depend on the correct mixture to achieve the expected performances, whether it is lower fuel consumption or power and speed [29][30][31][32].Carbon dioxide (CO 2 ) is a colorless, odorless gas, generated by the oxidation and combustion of hydrocarbon, as well as by living beings in the respiration process. It is a key gas for the greenhouse effect, and the increase of its levels, in the presence of other gases, is related with atmospheric pollution. It is also the key gas on the oxygen production by the photosynthesis process. The accumulation of this gas in enclosed spaces can be responsible to s...

show abstract

Section: Metal Oxide Semiconductorsmentioning

confidence: 99%

IoT-Enabled Gas Sensors: Technologies, Applications, and Opportunities

Gomes

Rodrigues

Rabêlo

et al. 2019

JSAN

View full text Add to dashboard Cite

show abstract

“…Metal oxide (MOX) semiconducting gas sensors are used in many different applications such as air quality monitoring [1] or fire detectors [2] because of their low cost and good sensitivity. However, their use also introduces unpleasant shortcomings such as cross-sensitivity, drift or aging [3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

A Compact, Reliable and Efficient 16 Channel Power Supply for the Automated Screening of Semiconducting Metal Oxide Gas Sensors

et al. 2019

View full text Add to dashboard Cite

The choice of suitable semiconducting metal oxide (MOX) gas sensors for the detection of a specific gas or gas mixture is time-consuming since the sensor’s sensitivity needs to be characterized at multiple temperatures to find its optimal operating conditions. To obtain reliable measurement results, it is very important that the power for the sensor’s integrated heater is stable, regulated and error-free (or error-tolerant). Especially the error-free requirement can be only be achieved if the power supply implements failure-avoiding and failure-detection methods. The biggest challenge is deriving multiple different voltages from a common supply in an efficient way while keeping the system as small and lightweight as possible. This work presents a reliable, compact, embedded system that addresses the power supply requirements for fully automated simultaneous sensor characterization for up to 16 sensors at multiple temperatures. The system implements efficient (avg. 83.3% efficiency) voltage conversion with low ripple output (<32 mV) and supports static or temperature-cycled heating modes. Voltage and current of each channel are constantly monitored and regulated to guarantee reliable operation. To evaluate the proposed design, 16 sensors were screened. The results are shown in the experimental part of this work.

show abstract

“…During the last several decades, considerable advances in gas sensor technology have been achieved in various applications such as: safety devices [1], environmental monitoring [2], air quality control [3], and health diagnosis [4]. Metal oxide (MOx) semiconductors have become promising gas sensors due to their low cost, short response time, long life and wide range target selectivity [5].…”

Section: Introductionmentioning

confidence: 99%

Thermal and Electrical Investigation on LTCC Gas Sensor Substrates

Rydosz¹,

Maziarz²,

Pisarkiewicz³

et al. 2016

IJIEE

View full text Add to dashboard Cite

Abstract-Metal Oxide (MOx) semiconductor gas sensors typically operate at temperatures of few hundred Celsius degrees and consume hundreds of miliwatts of power. It is therefore, essential, to investigate the heat flux and power consumption in MOx sensors, especially designed for applications in battery-powered devices. The work presents the thermal and electrical investigations on LTCC substrates (Low Temperature Cofired Ceramic) as a base material for gas sensors. A novel shape of substrates with reduced heat capacity is showed. The sensor temperature was modulated with a pulsed heater voltage, therefore decreasing the average power consumption.Index Terms-LTCC, gas sensors, thermal investigation, metal oxide. I. INTRODUCTIONDuring the last several decades, considerable advances in gas sensor technology have been achieved in various applications such as: safety devices [1], environmental monitoring [2], air quality control [3], and health diagnosis [4]. Metal oxide (MOx) semiconductors have become promising gas sensors due to their low cost, short response time, long life and wide range target selectivity [5]. Therefore, numerous researchers presented the investigation results on the following oxides: CuO [6] [12], ZnO [13], etc. Different metal oxide based materials have different reaction activation to the target gases. The chemical and physical processes of working sensors are well known [14], but still sensors behaviours are investigated. However, it is well known that the operating temperature is the most important factor that influences the performance of semiconductor gas sensors. The MOx sensors usually work in o C temperature range [15]. To provide such elevated temperatures a heater is usually embedded into gas sensors substrates. Depending on expected working temperature and substrate built, the consumed power can reach the level of hundreds of miliwatts. The power consumption of gas sensors can be reduced by using a pulsed operation mode, gas sensitive layers working at lower temperatures, changes in substrate design and materials [16]. The search for suitable substrate for Manuscript received December 9, 2014; revised February 13, 2016 Fig. 1 shows the concept of a complete gas sensing device which consists of few elements such as: gas sensitive layer, gas sensor substrate, package, front-end electronics and signal processing. For developed gas sensors the authors used TO-5 package. The electrical connections between sensors pads and case pins were welded with a 0.5 mm thick Pt wire. Fig . 2 shows the gas sensors based on LTCC substrate mounted in TO-5 package. The response of MOx sensors is influenced by various factors, i.e. gas concentration, temperature, gas flow, humidity etc. To provide suitable temperature in a sensitive region, an uniform temperature distribution is required. Therefore, the temperature distribution is a crucial issue that have to be taken into consideration. The temperature distribution in a modified gas sensor substrates was previously reported in [21]. Briefly, it is...

show abstract

Metal oxide semiconductor gas sensors in environmental monitoring

Cited by 50 publications

References 97 publications

IoT-Enabled Gas Sensors: Technologies, Applications, and Opportunities

IoT-Enabled Gas Sensors: Technologies, Applications, and Opportunities

A Compact, Reliable and Efficient 16 Channel Power Supply for the Automated Screening of Semiconducting Metal Oxide Gas Sensors

Thermal and Electrical Investigation on LTCC Gas Sensor Substrates

Contact Info

Product

Resources

About