Study of the Effect of Annealing Temperature on the Structural and Electrical Properties of Zinc Oxide Nanofilms Deposited by Pulsed Laser Technology for the Manufacture of Freon Gas Sensor R410a (CHF2 CH3/F2 CH2)
Department of Physics, College of Education, University of Tikrit/Iraq
Specialty: Laser and Molecular Spectrum/Iraq
Abstract
Zinc oxide (ZnO) nanomembranes were prepared by pulsed laser deposition technique (PLD), the membrane deposition occurred through the interaction between the falling laser rays with the atoms of the target material, then the plasma state inside the sedimentation chamber is formed upwards towards the sedimentation bases installed higher than the disk (target) at a distance of 20 mm, and the vacuum pressure (10-3) mbar The membranes are deposited and grow on the surface of the quartz base so that the distance between the target material and the laser rays is (150 mm), with a annealing temperature of different values (550, 750, 950) °C and a time of two hours on quartz slices, the effect of annealing temperature change on structural properties, surface topography and electrical was studied using XRD, AFM, SIM, Hall effect testers, gas sensor devices, this is for the purpose of knowing the nature of the surface of the prepared membrane and observing the change in granular size with increasing annealing temperatures after sedimentation, it was found that the average grain size (42.16) nm, the scanning electron microscopy examination showed that the grain size increases with increasing annealing temperature, that the structures are all nano, and that the elements that make up the membrane are zinc and oxygen, which were illustrated by the X-ray energy dispersion spectroscopy (EDX). Tests of the Hall effect phenomenon of the samples showed that they are n-type and that conductivity, Hall modulus and electrical mobility increase with increasing annealing temperature, the continuous conductivity test (D.C) showed that the electrical conductivity increases with the temperature of annealing and that the activation energy increases in order with the temperature change within the range (90-180) °C more than within the range (30-90) °C, the results of the examination of the gas sensor with different operating temperature showed that the best value of sensing in plasticized samples with a temperature of 750 °C, which is typical samples, as a sensor layer was formed that appears to be active, where the conductivity changes when exposed to gas.
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