Uses of Nanotechnology to Improve Infrared Sensors

1
Uses of Nanotechnology to Improve Infrared Sensors

• Joseph Dvorak
• ECEN 5060 Fundamentals of Nanotechnology
• Oklahoma State University

2
Introduction

• Current state of infrared technologies
• Quick overview of infrared theory
• Nanotechnologys contributions to improve
  infrared sensors
• The future of infrared sensors and nanotechnology

3
Infrared Overview

• Infrared radiation is the region of the
  electromagnetic spectrum from 720nm to 1000µm and
  includes the radiation naturally emitted by
  objects at room temperature.
• It has long been used by the military, although
  recently commercial and industrial uses have
  begun to appear.
• Main limitations are the necessary trade-offs
  between
• cost
• bulky and complex equipment
• response time
• image quality
• sensitivity

4
Infrared Theory

• Plancks Law
• Electrical resistance dependent on Temperature
• Thermal Expansion
• Photon Capture

5
Solutions from Nanotechnology

• Thermal Approaches
• Microbolometers
• Microcantilevers
• Quantum Approaches
• Quantum Dots
• Carbon Nanotube-Based Devices

6
Microbolometers

• Infrared Radiation causes a temperature change in
  the suspended plate which changes its electrical
  resistance.
• Essentially a larger scale object that after
  undergoing many size reductions is in the
  nanoscale.
• To maintain thermal isolation of the plate, the
  sensor must be packaged in a vacuum and
  maintained at that vacuum.

• One of the most advanced infrared detectors to
  use nanotechnology as they are already on the
  market.
• In the future, feature size reductions are
  expected.

7
Microcantilevers

• A thermal infrared detector that utilizes
  different rate of expansion for different
  materials
• Device is measured in micrometers, but feature
  sizes are in the nanometer range
• Currently under development

8
Quantum Dots

• A photon counting method of detecting infrared
  radiation
• The quantum dots are generally measured in the
  single digit nanometers

• Quantum dots are small enough that size begins to
  dictate electrical properties
• Can trap an electron in three dimensions to
  improve sensitivity
• Much current work is focused on quantum dots in a
  quantum well

9
Carbon Nanotube-Based Devices

• Photon detection method for sensing infrared
  radiation that utilizes carbon nanotubes
• Since the characteristics of carbon nanotubes can
  change with diameter and angle of carbon atom
  pattern, picking certain values makes the carbon
  nanotube sensitive to infrared radiation
• The size of a carbon nanotube, only allows the
  electron to travel in one dimension making carbon
  nanotubes very useful for implementing across
  contacts

• Still in the very early stages of development

10
Future Possibilities

• Low cost, room temperature, simple infrared
  detectors based on nanotechnology will find many
  uses
• Automotive Safety and Control
• Industrial and Construction safety
• Industrial Process Control
• Security Systems

11
Conclusion

• The widespread adoption of infrared systems will
  require several improvements
• Two primary methods exist to detect infrared
  radiation
• Nanotechnology has the potential to improve
  infrared technologies in several ways, including
  the four mentioned here
• Solving these challenges in infrared sensing
  systems can result in applications that will
  greatly improve peoples lives and/or safety

12
Image References

• Hunter, Scott R., Gregory Maurer, Lijun Jiang,
  and Gregory Simelgor. 2006. High-sensitivity
  uncooled microcantilever infrared imaging arrays,
  edited by F. A. Bjorn, F. F. Gabor and R. N.
  Paul SPIE.
• Krishna, Sanjay. 2005. InAs/InGaAs quantum
  dots-in-a-well photodetectors. 5957. Infrared
  Photoelectronics. Warsaw, Poland
• Yon, J J, L Biancardini, E Mottin, J L Tissot,
  and L Letellier. 2003. Infrared microbolometer
  sensors and their application in automotive
  safety. 7th International Conference on Advanced
  Microsystems for Automotive Applications, May 23,
  2003. Berlin.
• Zhang, Jiangbo, Ning Xi, Hoyin Chan, and
  Guangyong Li. 2006. Single carbon nanotube based
  infrared sensor. 6395. Electro-Optical and
  Infrared Systems Technology and Applications
  III. Stockholm, Sweden.
• Other references for the topics listed here are
  included in the associated paper to this
  presentation. They have been omitted here to
  save space.