1. Nanoengineered, Low-Power, and Low
Cost Chemical Sensors for
Environmental Monitoring
Nichole Sullivan,
Ratan Debnath, and Abhishek Motayed 1

2. 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)
2

3. N5’s Single-Chip Solution
N5 Sensors Inc.
3
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

4. Highlights of our Technology
• GaN backbone
• Nanophotocatalytic surface functionalization
• Room temp operation
• Highly scalable
N5 Sensors Inc.
4

5. N5’s Fabrication
• National Institute of Standards and Technology Class 100 Cleanroom 5
N5’ Wafer Design
ASML Stepper
Lithography
RF Sputtering
Functional Layer Deposition
Inductively Coupled Plasma Etch
Microstructure Etch
SensorDesigns
N5Team
Wafer Lot Final Patterned Wafer
Packaged Sensors
Single Die Containing
Several Microsensors
Supplied by
NTT- AT
Commercial Vendor

6. Sensor Testing Facility
• Capable of mixing 8 gases
• Compressed air cylinders for gases
• Bubbler baths for any organic compounds
• Fully controlled using Labview
6
Non-CorrosiveCorrosive
N5 Sensors Inc.

7. Analyte Response
N5 Sensors Inc.
7
H2 (10%)
CO (5000 ppm)
NO2 (500 ppm)
H2 on
H2 off
CO on
CO off
NO2 on
NO2 off

8. Selectivity
N5 Sensors Inc.
Target Analyte
Range
Detected
Sensitivity (%) T90 (s) T10 (s)
Hydrogen - H2 25 ppm – 1 % 8 100 70
Nitrogen Dioxide – NO2 50 ppm - 1% 5 30 60
Carbon dioxide – CO2 0.5% 2 50 100
8
Time
Presence of Target Analyte
Chemical
sensor chip
Microsensor
arrays
Photocatalytic
nanoclusters
Current
(Sensor Output)
Individual sensor
Electrode
Substrate
Active Area
Analyte
O
O-
Photocatalytic
MOx
M
M
M
M
GaN
O
H
Photocurrent
e- e-
e-
+
+
+ +
e-
Sensitivity (%) = (Rgas‐ Rair)/Rair

9. Sensor Robustness
• Long term exposure
• Wide temperature range
• Recover after condensing water
N5 Sensors Inc.
9
10% H2 in breathing air
y = 195x + 134.6
R2 = 0.9921
Sensitivity (%) = (Rgas‐ Rair)/Rair

10. Applications
• First Responders/Hazmat
• Environmental monitoring
• Personal monitoring
• Medical Research
• Monitoring the Portable Life Support System (PLSS)
N5 Sensors Inc.
10

11. • 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
11

12. 12
Analyte
Range 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 NA
Chlorine – 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 70
Oxygen – O2 10 - 30% 20 RH/ 20 C 40 10 40
Carbon dioxide – CO2 0.1 - 1% 20 RH/ 20 C 2 50 100
Carbon monoxide - CO 10 – 300 ppm 20 RH/ 20 C 15 80 150
Nitrogen Dioxide – NO2 100 – 500 ppm 20 RH/ 20 C 2 100 150
Methane – CH4 0.5 – 10% Not Measured/In progress
Hydrogen sulfide – H2S 1 – 100 ppm Not Measured/In progress
Sulfur dioxide - SO2 1 – 100 ppm Not Measured/In progress
Combustible (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.