jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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sensing and sensors16-722 - S2004

F 9a30-12p20 NSH1305

Jen Morris <jenmorris@cmu.edu>

+1 412 268 3303

office: HH A313

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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L2004-10A

Solid-state Chemical Sensors and Chemical Sensor Arrays

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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Bibliography

• Figaro Engineering, Inc. – http://www.figarosensor.com/

• MicroChemical Systems SA– http://www.microchemical.com/– http://www.sensors.com.cn/download/MiCS/

• Cyrano Sciences, Inc.– http://cyranosciences.com/

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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Solid-State Chemical Sensors

• Metal-oxide semiconductor layer– Usually tin dioxide (SnO2)

• Apply heat – In air

• Surface oxygen increases (negatively charged)• Resistance increases

– In presence of deoxidizing gas• Surface oxygen decreases• Resistance decreases

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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How They Work

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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Figaro Engineering, Inc.

• Chemical gas sensors– LP-Gas/Propane (500-10000ppm)

– Natural gas/Methane (500-10000ppm)

– General combustible gas (500-10000ppm)

– Hydrogen (50-1000ppm)

– Carbon monoxide (50-1000ppm)

– Ammonia (30-300ppm)

– Hydrogen sulfide (5-100ppm)

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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Figaro TGS 2442

• Carbon Monoxide Sensor

• Applications:– CO detectors– Air quality controllers– Indoor parking lot ventilation

• Gas sensing layer– Tin dioxide (SnO2)

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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Figaro TGS 2442• Features:

– Low power consumption

– High sensitivity/selectivity to carbon monoxide (CO)

– Miniature size

– Low sensitivity to alcohol vapor

– Long life and low cost

– Low humidity dependency

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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TGS 2442 Basic Measuring Circuit

• 1 second heating cycle• 1 second circuit voltage cycle

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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TGS 2442 Specifications

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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SnO2 for CO Sensing

• Rs = Sensor resistance of displayed gases • Ro = Sensor resistance in 100ppm CO

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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SnO2 for CO Sensing

• Rs = Sensor resistance at 30ppm, 100ppm and 300ppmof CO at various temperatures and 50%R.H.

• Ro = Sensor resistance at 300ppm of CO at 25°C and 50% R.H.

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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MicroChemical Systems SA

• Chemical gas sensors– Ozone (0.01-10ppm) – Nitrogen Dioxide (0.05-5ppm) – Ethanol (50-1000ppm)

– CO / NO2 (1-400ppm/0.05-5ppm)

– Carbon Monoxide & HCs (1-400ppm)

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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MicroChemical Systems MiCS-3110

• Ethanol Sensor

• Applications:– Breathalizer: (Blood Alcohol Content)– Various industrial applications

• Gas sensing layer– Tin dioxide (SnO2)

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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MicroChemical Systems MiCS-3110• Features:

– Low heater current

– Wide detection range

– High sensitivity

– Fast thermal response

– Electro-Static Discharge protected

– Miniature dimensions

– High resistance to shocks and vibrations

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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MiCS-3110 Basic Measuring Circuit

• Run in constant voltage mode• Heater voltage of VH = 2.4 V

– increases temperature of Rs to 430°C

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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MiCS-3110 Specifications

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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SnO2 for Ethanol Sensing

• RS = Sensor resistance to C2H5OH • R10ppm = Sensor resistance resistance in 10 ppm of C2H5OH

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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Chemical Sensor Arrays

• Array of polymer composite sensors

• Swell in presence of vaporized analyte– Conductive polymer pathways broken– Resistance increases

• Different gases produce different responses

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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Cyrano Sciences, Inc. Cyranose® 320

• Hand-held chemical vapor sensor

• 32 thin-film carbon-black chemiresistors

• Trained by taking different measurements– Create a database of patterns– Match odors against saved patterns

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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Cyranose® 320 Specifications

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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Cyrano Sciences, Inc. NoseChipTM

• Under development– Low cost, low power, lightweight sensing – Optional short-range wireless capability

• Applications– Sensing nodes for facilities protection – Personal badge detectors for toxic

industrial chemicals and chemical warfare agents

– Residual life indication – Leak detectors in military or commercial

systems – Quality monitors in embedded systems

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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NoseChipTM Specifications

jenmorris@cmu.edu 16-722 L2004-10A (solid-state chemical sensors)

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Bibliography

• Figaro Engineering, Inc. – http://www.figarosensor.com/

• MicroChemical Systems SA– http://www.microchemical.com/– http://www.sensors.com.cn/download/MiCS/

• Cyrano Sciences, Inc.– http://cyranosciences.com/