Republic of IraqMinistry of Higher Education and Scientific Research         University of Al-Mustansiriya             Col...
Abstract Nanostructured TiO2 thin films are grown by pulsed laser  deposition (PLD) technique on glass substrates. TiO2 t...
 AFM measurements confirmed that the films grown by this  technique have good crystalline and homogeneous surface.  The R...
Why titanium dioxide (TiO2)?  Non-toxic, inexpensive, highly photoactive, and easily  synthesized and handled. Highly pho...
The Crystal Structure of TiO2       Anatase                 Rutile                Brookite form is tetragonal     form is ...
Applications of Nanostructured TiO2 Hydrophilic properties for environmental applications, such  as air purification, ste...
 Dye-sensitized solar cells (DSSC). TiO2/polymer nanocomposites. Gas sensors.
Mechanism of Pulsed Laser DepositionThe mechanism of the PLD process can be expressed in threesteps : The interaction of ...
Pulsed laser deposition (PLD) The target material is  ablated by a Nd: YAG                  Nd: YAG  Laser. The ejected ...
Aim of the Work Initially, the series of samples has been prepared by PLD  technique at different technological condition...
Experimental   Work
Experimental work                       Thin films                        By PLD                     Annealing films at   ...
Target preparation of TiO2(a) before                    (b) after             The target before and after being
Parameters Used Laser model: Q-switched Nd: YAG Laser Second Harmonic Generation (SHG). Laser wavelength 532 nm. Energy...
Pulsed Laser Deposition (PLD)
Nanostructured TiO2 Thin films
Characterization measurements1.   Thickness measurement
Characterization measurements2. X-ray Diffraction (XRD)             Shimadzu 6000 made in Japan
Characterization measurements3. Atomic Force Microscopy   4. Optical measurements   (AFM)
Results
X-ray Diffraction• All the films were polycrystalline.    • Good agreement with JCPD data card• Films annealed at 500 °C a...
Table 1: Lattice constants and interpllanar spacing of TiO2 films.Temperature      2θ                Interplanar      Latt...
Full Width at Half Maximums (FWHM) decreases with increasing of annealing temperatureGrain size increase with increasing o...
Atomic Force Microscopy (AFM)
AFMTable 3: Morphological characteristicsfrom AFM images for TiO2 thin film.                                              ...
Optical Properties     1.   Optical Transmission (T)Average transmittance of as-deposited TiO2 films is about 65% in the n...
Optical Properties2. Optical Absorption (A)
Optical Properties   3. Optical Absorption Coefficient (α)The absorption coefficient (α) is increasing with the annealing ...
Optical Properties4. Optical Energy Gap (Eg)
Optical Properties  4. Optical Energy Gap (Eg)                                                          •    Table 4: Show...
Optical Properties5.   The values of the refractive index   6.   Extinction coefficient (Ko) increasing     (n) for the fi...
Optical Properties     7. The Dielectric Constants (Ԑ Ԑ                                  r, i)•   Real part and imaginary ...
Optical Properties     8. Optical Conductivity (σ)•   The optical conductivity of the films increases with increasing of a...
Conclusion The XRD results reveal that the deposited thin film and annealed at 400 C of TiO2  have a good nanocrystalline...
Conclusion Also optical properties of TiO2 thin films show that the films have allowed direct  transition and allowed ind...
Future Work Effect of annealing on the electrical properties of nanostructure TiO2  films prepared by PLD. Study of stru...
Publications “Annealing Effect on the growth nanostructured TiO2 thin films by  pulsed laser deposition (PLD),” Accepted ...
T H ANK Y U  iO2 For Listening
Effect of Annealing on the Structural and       Optical Properties of Nanostructured TiO2 Films Prepared By PLD
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Effect of Annealing on the Structural and Optical Properties of Nanostructured TiO2 Films Prepared By PLD

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Effect of Annealing on the Structural and Optical Properties of Nanostructured TiO2 Films Prepared By PLD . تأثير التلدين على الخواص التركيبية والبصرية لأغشية أوكسيد التيتانيوم (TiO2) ذات التراكيب النانوية المحضرة بتقنية ترسيب الليزر النبضي (PLD)

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  • My search titled ……..
  • this figure shown Shadowgraph of plume . this figure shown Growth Modes (a) Frank-Van der Merwe; (b) Volmer-Weber; (c) Stranski-Krastanov.
  • The deposition of thin films pld and then annealing at 400, 500 & 600. we measured. And we measured. And we measured.
  • These figures shown target : a. before ablation process and b. after ablation process
  • We are seeing device pulsed laser deposition located in University of technology.
  • we are seeing thin films deposited at 300 and thin films annealed at 400, 500 and 600
  • Optical interferometer method for measuring thickness
  • X-ray diffraction for measuringof structural properties
  • In fact we published three research
  • Effect of Annealing on the Structural and Optical Properties of Nanostructured TiO2 Films Prepared By PLD

    1. 1. Republic of IraqMinistry of Higher Education and Scientific Research University of Al-Mustansiriya College of Education A thesis submitted By Sarmad Sabih Kaduory Al-Obaidi Supervised by Dr.Ali Ahmed Yousif Al-Shammari (Assistant Professor)
    2. 2. Abstract Nanostructured TiO2 thin films are grown by pulsed laser deposition (PLD) technique on glass substrates. TiO2 thin films are then annealed at 400-600 °C in air for a period of 2 hours. Effect of annealing on the structural, morphological and optical properties are studied. The results of the X-ray testing show that all nanostructures tetragonal are polycrystalline, also these results show that increasing in grain size with increasing of annealing temperature. The XRD results also reveal that the deposited thin film and annealed at 400 °C of TiO2 have anatase phase. Thin films annealed at 500 °C and 600 °C have mixed anatase and rutile phase.
    3. 3.  AFM measurements confirmed that the films grown by this technique have good crystalline and homogeneous surface. The Root Mean Square (RMS) value of thin films, surface roughness increased with increasing annealing temperature. From UV-VIS spectrophotometer measurements, the optical transmission results shows that the transmission over than ~65% which decrease with the increasing of annealing temperatures. The allowed indirect optical band gap of the films was estimated to be in the range from 3.49 to 3.1 eV. The allowed direct band gap was found to decrease from 3.74 to 3.55 eV with the increase of annealing temperature. The refractive index of the films was found from 2.1-2.8 in the range from 350nm to 900nm. The extinction coefficient, real and imaginary parts of the dielectric constant increase with annealing temperature.
    4. 4. Why titanium dioxide (TiO2)? Non-toxic, inexpensive, highly photoactive, and easily synthesized and handled. Highly photostable. High electro-chemical properties and high chemical stability. Wide band gap (Eg 3 eV). High refractive index - up to 2.7 (at wavelength of 600nm). High dielectric constant and hardness.
    5. 5. The Crystal Structure of TiO2 Anatase Rutile Brookite form is tetragonal form is tetragonal form is orthorhombic 3.9 gm/cm3 4.23 gm/cm3 4.13 gm/cm3a = b = 3.7710 Å and a = b = 4.5933 Å and a = 9.18 Å, b = 5.447 Å c = 9.430 Å c = 2.9592 Å and c = 5.145 Å n= 2.5612 n= 2.605 n= 2.5831
    6. 6. Applications of Nanostructured TiO2 Hydrophilic properties for environmental applications, such as air purification, sterilization, anti fogging, and self cleaning. Biomedical applications . Photocatalysis.
    7. 7.  Dye-sensitized solar cells (DSSC). TiO2/polymer nanocomposites. Gas sensors.
    8. 8. Mechanism of Pulsed Laser DepositionThe mechanism of the PLD process can be expressed in threesteps : The interaction of the laser beam and target. Plasma Plume Formation. Nucleation and growth of thin films.
    9. 9. Pulsed laser deposition (PLD) The target material is ablated by a Nd: YAG Nd: YAG Laser. The ejected material forms a plasma plume and expands across to the substrate where it is Halogen deposited as a film. Lamp The substrate is heated by a halogen lamp. A background gas is used to control the plume stoichiometry and dynamics.
    10. 10. Aim of the Work Initially, the series of samples has been prepared by PLD technique at different technological conditions on glass substrates. We study the preparation condition such as, substrate temperature, oxygen pressure, energy laser influence during deposition, as well as the concentration into the target on the structure, morphology (Atomic Force Microscopy (AFM)), and XRD. Also the optical properties for deposited films. Then, we study the effect of annealing temperature on structural and optical properties of TiO2 films.
    11. 11. Experimental Work
    12. 12. Experimental work Thin films By PLD Annealing films at :400 oC, 500 oC& 600 oC Thickness Structural Opticalof thin films Properties Properties Optical T, A, α, Eg, n,interferometer XRD & AFM kₒ,εr, εi & ζ method
    13. 13. Target preparation of TiO2(a) before (b) after The target before and after being
    14. 14. Parameters Used Laser model: Q-switched Nd: YAG Laser Second Harmonic Generation (SHG). Laser wavelength 532 nm. Energy density 0.4 J/cm2. Pulse duration 10 ns. Substrate temperature of 300 °C. Pressure of 10-2 mbar.
    15. 15. Pulsed Laser Deposition (PLD)
    16. 16. Nanostructured TiO2 Thin films
    17. 17. Characterization measurements1. Thickness measurement
    18. 18. Characterization measurements2. X-ray Diffraction (XRD) Shimadzu 6000 made in Japan
    19. 19. Characterization measurements3. Atomic Force Microscopy 4. Optical measurements (AFM)
    20. 20. Results
    21. 21. X-ray Diffraction• All the films were polycrystalline. • Good agreement with JCPD data card• Films annealed at 500 °C and 600 °C have mixed anatase and rutile phase structure.
    22. 22. Table 1: Lattice constants and interpllanar spacing of TiO2 films.Temperature 2θ Interplanar Lattice constant Å (hkl) c/a ( oC) (degree) spacing, d Å a cAs-deposited 25.27 A(101) 3.15 3.3439 / 2.842 at 300 37.83 A(004) 2.37 / 9.5050 25.2 A(101) 3.53 3.8 / 400 37.81 A(004) 2.37 / 9.5098 3.502 48.1 A(200) 1.89 3.7803 / 25.17 A(101) 3.53 3.8 / 37.79 A(004) 2.38 / 9.5147 500 3.503 48.12 A(200) 1.89 3.7788 / 27.47 R(110) 3.24 4.5881 / 25.11 A(101) 3.54 3.8170 / 37.72 A(004) 2.38 / 9.5317 600 48 A(200) 1.89 3.7877 / 2.497 27.41 R(110) 3.25 4.5979 / 54.35 R(211) 1.68 / 2.9484
    23. 23. Full Width at Half Maximums (FWHM) decreases with increasing of annealing temperatureGrain size increase with increasing of annealing temperatureValues of texture coefficient decrease with increasing of annealing temperature Table 2: The obtained result of the structural properties from XRD for TiO2 thin films. Main Temperature 2θ Stress Ss Strain δ (hkl) FWHM Grain Texture Tc ( oC) (degree) (GPa) 10-3) Size (nm) As-deposited 25.27 A(101) 0.450 19.02 0.218 0.9354 1.813 at 300 37.83 A(004) 0.440 19.94 25.2 A(101) 0.421 20.19 400 37.81 A(004) 0.098 0.4225 0.412 21.27 1.126 48.1 A(200) 0.410 22.16 25.17 A(101) 0.352 24.16 37.79 A(004) 0.400 21.94 500 -0.019 0.084 1.154 48.12 A(200) 0.349 25.99 27.47 R(110) 0.334 25.59 25.11 A(101) 0.301 28.25 37.72 A(004) -0.435 1.8709 0.288 30.43 600 48 A(200) 0.338 26.88 0.952 27.41 R(110) 0.315 27.13 0.849 3.640 54.35 R(211) 0.293 31.85
    24. 24. Atomic Force Microscopy (AFM)
    25. 25. AFMTable 3: Morphological characteristicsfrom AFM images for TiO2 thin film. • The root mean square Root Mean SquareTemperature (oC) Roughness average (RMS) (RMS) and surface (nm) (nm) roughness increased As-deposited at 46.5 60.5 300 with increasing of 400 76.6 95 annealing temperature 500 84.3 105 600 88.6 114
    26. 26. Optical Properties 1. Optical Transmission (T)Average transmittance of as-deposited TiO2 films is about 65% in the near-infrared regionFor all the films transmittance decreases with increasing of annealing temperature
    27. 27. Optical Properties2. Optical Absorption (A)
    28. 28. Optical Properties 3. Optical Absorption Coefficient (α)The absorption coefficient (α) is increasing with the annealing temperature increasing
    29. 29. Optical Properties4. Optical Energy Gap (Eg)
    30. 30. Optical Properties 4. Optical Energy Gap (Eg) • Table 4: Shows allowed direct band gap and allowed indirect band gap for different From table 4. it can be annealing temperatures of TiO2 thin films. observed that (Eg) is decreasing with the Allowed direct Allowed indirect increasing of annealingTemperature (oC) band band gap (eV) gap (eV) temperature for all films.As-deposited at 300 3.74 3.49 400 3.7 3.39 500 3.68 3.35 600 3.55 3.1
    31. 31. Optical Properties5. The values of the refractive index 6. Extinction coefficient (Ko) increasing (n) for the films of different with increasing of annealing annealing temperatures vary in the temperature. range from 2.1 to 2.8.
    32. 32. Optical Properties 7. The Dielectric Constants (Ԑ Ԑ r, i)• Real part and imaginary part increases when the annealing temperature increasing.
    33. 33. Optical Properties 8. Optical Conductivity (σ)• The optical conductivity of the films increases with increasing of annealing temperature.
    34. 34. Conclusion The XRD results reveal that the deposited thin film and annealed at 400 C of TiO2 have a good nanocrystalline tetragonal anatase phase structure. Thin films annealed at 500 C and 600 C have mixed anatase and rutile phase structure. The AFM results show the slow growth of crystallite sizes for the as-grown films and annealed films from 400 to 600 C. The root mean square (RMS) is found to increase from 50.5 to 114 nm as the annealing temperature is increased up to 600 C. The average transmittance (T) of deposited TiO2 films is about 65% in the near- infrared region. The film annealed at 600 C has the least transmittance among the films, therefore; the film is good to be detector within ultra-violet region range. The optical absorption coefficient (α) of TiO2 films is about (α>104cm-1), thus absorption coefficient has higher increase at wavelength (λ<400 nm). This converts to a large probability that direct electronic transition will happen.
    35. 35. Conclusion Also optical properties of TiO2 thin films show that the films have allowed direct transition and allowed indirect transition. Increasing of the annealing temperature for all films cause a decrease in the optical band gap value and an increase in the optical constants (refractive index (n), extinction coefficient (Ko), real (εr) and imaginary (εi) parts of the dielectric constant).
    36. 36. Future Work Effect of annealing on the electrical properties of nanostructure TiO2 films prepared by PLD. Study of structural, optical and electrical properties of nanocrystalline TiO2 films prepared by Chemical Spray Pyrolysis. Studying the effect of different preparation conditions on the photolumincent efficiency and Scanning Electron Microscopy (SEM) of the prepared samples. Study of nanostructured TiO2 thin films prepared by PLD for gas sensor applications.
    37. 37. Publications “Annealing Effect on the growth nanostructured TiO2 thin films by pulsed laser deposition (PLD),” Accepted at Journal of Eng. & Tech., University of Technology, No: 3291, (27/11/2012). “Synthesis of nanostructured TiO2 thin films by pulsed laser deposition (PLD) and the effect of annealing temperature on structural and morphological properties,” Accepted at Ibn Al-Haitham Jour. for Pure and Appl. Sci., University of Baghdad, No: 3/1791, (9/12/2012). “Study of Annealing Effect on the Some Physical Properties of Nanostructure TiO2 films prepared by PLD,” Journal of the college of the education, Al-Mustansiriya University, (2012), (constraint of bespreading).
    38. 38. T H ANK Y U iO2 For Listening

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