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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.