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Design and construction of low-pressure D. C.-sputtering plasma system for preparing gas sensors
Other Title(s)
تصميم و بناء منظومة الكاثود المتوهج في بلازما الضغط الواطئ و الترذيذ المستمر لتحضير متحسس غازي
Dissertant
Thesis advisor
Khalaf, Muhammad Khammas
al-Tamimi, Nadhirah Abbas Ali
Comitee Members
al-Hayif, Abd al-Husayn K.
al-Kazimi, Mahasin F. Hadi
Muhammad, Ghusun Hamid
Twij, Wisam Abd Ali
University
University of Baghdad
Faculty
College of Science
Department
Department of Physics
University Country
Iraq
Degree
Ph.D.
Degree Date
2013
English Abstract
In this work, a DC planar sputtering system has been successfully designed and fabricated.
The glow discharge plasma chamber was made of stainless steel with a length of 35 cm and a diameter of 31 cm.
This chamber consists of two stainless steel planar sputtering electrodes used as anode and cathode each of diameter of 10cm.
Electrical plasma properties have been studied via studying the currentvoltage, current-pressure, and Paschen curves.
The electrical plasma properties were studied at different inter-electrodes spacing, gas pressure, and argonoxygen mixture.
The adopted inter-electrodes spacing was 5cm.
We choose the left side from the Paschen minimum to study plasma parameters and to prepare the SnO2 thin films.
The best argon-oxygen mixture obeys this condition (Ar/O2=1/2).
The plasma parameters like electron temperature Te, electrons density ne, ions density ni, plasma potential VP and floating potential VF , were measured using single Langmuir probe with different gas pressures, and argon-oxygen mixture.
It is found that the electron temperature decreases and electron density increased with increasing the argon gas pressure and increasing the oxygen to argon mixed flow.
Three group of SnO2 thin films deposited using dc-plasma sputtering system on glass substrate with rate of deposition time 60min.
The first group was deposited with different discharge current (10, 15, 20, and 25mA).
The second group prepared at different gas pressure (0.15, 0.05, 0.035, and 0.015mbar).
The third group deposit with varying argon to oxygen mixed flow.
The structures of the films prepared on glass substrate were examined by X-ray diffraction analysis.
The results show that the structure is polycrystalline with tetragonal structure and preferential orientation in the (110), and(101) directions.
The increasing discharge current and decreased gas pressure enhance SnO2 thin films crystallite structure.
The optical measurements showed that the sputtered SnO2 films have direct energy gap (Eg) (4eV decreases to 3.92eV) with decreasing of gas pressure, and increased from 3.25eV to 3.97eV with increasing of oxygen flow respect to argon flow.
The surface morphology of SnO2 thin films have been studied by using Atomic Force Microscope and Scanning Electron Microscope .
The nano grain size value depended on discharge current, gas pressure, and Argon- Oxygen mixture flow.
The nano grain size value increased with increasing discharge current and gas pressure, and decreased with increasing Oxygen- Argon mixture flow.
The surface roughness increased with decreasing grain size .
The sensitivity of SnO2 samples to NO2 gas in air ambient has been measured in gas sensing system.
All samples were tested at mixed ratio (1%, 2%, and 3% NO2: air) and bias voltage (6 volt).
The optimal operating temperature is found to be 220oC for SnO2 samples.
The maximum sensitivity is (57%) with fast response time (2.7s) and recovery time of (7.2s).
Main Subjects
No. of Pages
125
Table of Contents
Table of contents.
Abstract.
Abstract in Arabic.
Chapter One : Introduction and theoretical part.
Chapter Two : Experimental work.
Chapter Three : Results and discussion.
References.
American Psychological Association (APA)
Ibrahim, Fuad Tariq. (2013). Design and construction of low-pressure D. C.-sputtering plasma system for preparing gas sensors. (Doctoral dissertations Theses and Dissertations Master). University of Baghdad, Iraq
https://search.emarefa.net/detail/BIM-607696
Modern Language Association (MLA)
Ibrahim, Fuad Tariq. Design and construction of low-pressure D. C.-sputtering plasma system for preparing gas sensors. (Doctoral dissertations Theses and Dissertations Master). University of Baghdad. (2013).
https://search.emarefa.net/detail/BIM-607696
American Medical Association (AMA)
Ibrahim, Fuad Tariq. (2013). Design and construction of low-pressure D. C.-sputtering plasma system for preparing gas sensors. (Doctoral dissertations Theses and Dissertations Master). University of Baghdad, Iraq
https://search.emarefa.net/detail/BIM-607696
Language
English
Data Type
Arab Theses
Record ID
BIM-607696