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Nanoengineered, Low-Power, and Low Cost Chemical Sensors for
Environmental Monitoring
Nichole Sullivan, Ratan Debnath, and Abhishek Motayed
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Current Sensor Technology• Bulky, power hungry, heavy - Inconvenient to carry• Require routine calibration, frequent maintenance, and
replacement – Difficult to interpret readings• Expensive – Acquisition and maintenance
N5 Sensors Inc. A photoionization (PID) based
VOC detector
A standard four-gas detector
(CO, H2S, LEL, and Oxygen)
A single toxic gas detector (HCN)
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N5’s Single-Chip Solution
N5 Sensors Inc.
Replaces multiple power-hungry sensor technologies with a arrays of microsensors on a single chip.
Catalytic/Pellistor
Toxic, Explosive, and Volatile Organic Compound Sensors – All in a chip!
Electrochemical
Photoionization
What our technology can offer
1 – Reduced Calibration, Maintenance, and
Replacement Burden
2 – Ease of Use
4 – Reduced Upfront Acquisition and
Downstream Maintenance Cost
3 – Additional Functionality
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Highlights of our Technology• GaN backbone• Nanophotocatalytic surface functionalization• Room temp operation• Highly scalable
N5 Sensors Inc.
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N5’s Fabrication
•National Institute of Standards and Technology Class 100 Cleanroom
N5’ Wafer Design
ASML StepperLithography
RF SputteringFunctional Layer Deposition
Inductively Coupled Plasma EtchMicrostructure EtchSe
nsor
Des
igns
N5
Team
Wafer Lot Final Patterned Wafer
Packaged Sensors
Single Die Containing Several Microsensors
Supplied byNTT- AT
Commercial Vendor
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Sensor Testing Facility• Capable of mixing 8 gases• Compressed air cylinders for gases• Bubbler baths for any organic compounds• Fully controlled using Labview
Non-Corrosive Corrosive
N5 Sensors Inc.
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Analyte Response
N5 Sensors Inc.
H2 (10%)
CO (5000 ppm)
NO2 (500 ppm)
H2 on
H2 offCO on
CO off
NO2 on
NO2 off
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Selectivity
N5 Sensors Inc.
Target AnalyteRange
Detected Sensitivity (%) T90 (s) T10 (s)
Hydrogen - H2 25 ppm – 1 % 8 100 70Nitrogen Dioxide – NO2 50 ppm - 1% 5 30 60Carbon dioxide – CO2 0.5% 2 50 100
Time
Presence of Target Analyte
Chemical sensor chip
Microsensor arrays
Photocatalytic
nanoclustersCurrent (Sensor Output)
Individual sensor
Electrode
Substrate
Active Area
OH
AnalyteO
O-H
Photocatalytic MOx
M
M
M
M
GaN
O
H
Photocurrente- e- e-+ ++ +
e-
Sensitivity (%) = (Rgas‐ Rair)/Rair
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Sensor Robustness• Long term exposure• Wide temperature range • Recover after condensing water
N5 Sensors Inc.
10% H2 in breathing air
y = 195x + 134.6
R2 = 0.9921
Sensitivity (%) = (Rgas‐ Rair)/Rair
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Applications• First Responders/Hazmat• Environmental monitoring• Personal monitoring• Medical Research• Monitoring the Portable Life Support System (PLSS)
N5 Sensors Inc. Multi-Sensor Chip Sensor Module
User Interface on a SmartphoneFirst Generation Prototype
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• University of Maryland spin-off founded 2012• Commercializing chip-scale sensors for industrial, commercial
and residential applications• Toxic chemicals and gases • Explosives• VOCs
• Patent-pending (US 13/861,962) hybrid nanocluster-semiconductor innovative sensors technology – N5 obtained exclusive license from UMD
• Over $900,000 in funding from TEDCO, EPA, NSF, DHS, ARMY, MIPS, and NIST
Company at a Glance
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AnalyteRange of Detection
Typical Humidity and Tem Sensitivity (%)= (Rgas‐ Rair)/Rair
T90 (s) T10 (s)
Ammonia – NH3 1 – 100 ppm 20 RH/ 20 C 15 250 NAChlorine – Cl2 0.5 – 10 ppm 20 RH/ 20 C 212 50 200
Hydrogen chloride – HCl
1 – 100 ppm 20 RH/ 20 C 74 60 NA
Hydrogen cyanide – HCN
1 – 100 ppm 20 RH/ 20 C 10 70 90
Hydrogen - H2 0.5 - 10% 20 RH/ 20 C 500 100 70Oxygen – O2 10 - 30% 20 RH/ 20 C 40 10 40
Carbon dioxide – CO2 0.1 - 1% 20 RH/ 20 C 2 50 100Carbon monoxide - CO 10 – 300 ppm 20 RH/ 20 C 15 80 150Nitrogen Dioxide – NO2 100 – 500 ppm 20 RH/ 20 C 2 100 150
Methane – CH4 0.5 – 10% Not Measured/In progressHydrogen sulfide – H2S 1 – 100 ppm Not Measured/In progress
Sulfur dioxide - SO2 1 – 100 ppm Not Measured/In progressCombustible (Lower Explosive Limit) LEL
1 -10% Not Measured/In progress
Mercury - Hg 0.1 mg/m Not Measured/In progress
Note – T90, T10 are response and recovery time as defined: T90 - time for the sensor to reach 90% of its max value in presence of analyte, T10 - time for the sensor to recover close to 10% of its base line value when the analyte is not present.Note – The humidity and temperature are typical. However, the lower and upper bounds can vary for different analytes.