Undergraduate Research Experience in Sensors and Applications – Summer 2013

University of Texas Arlington

Pyroelectric Infrared SensorsDr. Donald Buttler

Mid-Term Presentation

By

Dawit T. Woldemariam

July 16, 2013

Background

All objects above absolute zero emit light corresponding to their temperatures.

The hotter the object is the shorter the wavelength of the emitted light.

Infrared light is an electromagnetic radiation whose wavelength lies between visible light and microwave.

Pyroelectricity is the property of materials to produce a temporary voltage when heated.

Pyroelectric coeficient tells the sensitivity of the material ; the higher the pyroelectric coefficient the more the current produced will be up on heating.

Research Objective

To design a material with the highest possible pyroelectric coefficient to be used in infrared sensor designs.

i=A* P * (dT/dt)

Research Procedure

1. Deposition of PZT on to a substrate

2. measuring the temperature ramp (dT/dt) using a temperature controller

3. measuring capacitances at different temperatures using an LCR meter for device characterization

4. measuring the piezoelectric current using a parallel resistor and a multimeter

Deposition of PZT/PCT on to a substrate A measured amount of PZT is deposited on to a silicon-Gold

wafer using pulsed laser deposition (PLD) technique

Why PZT? PZT (Lead Zicronate Titanate ) has a high dielectric

constant and exhibits a strong ferroelectricity. The higher dielectric constant increases the

capacitance , while a strong ferroelectricity produces higher pyroelectric current.

.

Measuring Temperature Ramp The temperature ramp is measured by increasing the

temperature and recording the time.

Capacitance measurment Measuring capacitance vs time is important in determining

different characterstics of the device such as breakdown voltage and conductivity with time

Measurement setup

Thermal ChuckLCR meter

Probe stationgfgf

Application Areas

Infrared sensors in general Some examples : night vision cameras, hospital surgical

devices