Chromium Doped TiO2 Sputtered Thin Films: Synthesis, Physical Investigations and Applications (SpringerBriefs in Applied Sciences and Technology)

This book presents co-sputtered processes ways to produce chrome doped TiO 2 thin films onto various substrates such as quartz, silicon and porous silicon. Emphasis is given on the link between the experimental preparation and physical characterization in terms of Cr content. Moreover, the structural, optical and optoelectronic investigations are emphasized throughout. The book explores the potencial applications of devices based on Cr doped TiO 2 thin films as gas sensors and in photocatalysis and in the photovoltaic industry. Also, this book provides extensive leads into research literature, and each chapter contains details which aim to develop awareness of the subject and the methods used. The content presented here will be useful for graduate students as well as researchers in materials science, physics, chemistry and engineering. Acknowledgments 6 Contents 7 Introduction 10 Abstract 12 1 TiO2 Properties and Deposition Techniques 13 Abstract 13 1.1 Introduction 13 1.2 Crystallographic, Electronics and Optics Structures of TiO2 13 1.2.1 Crystallographic Properties of TiO2 [1] 13 1.2.2 Electronic Properties of TiO2 14 1.2.3 Optical Properties of TiO2 15 1.3 Implementation Technique of the TiO2 16 1.3.1 Chemical Methods 16 1.3.2 Physical Method [Physical Vapor Deposition (PVD)] 18 1.4 Effect of Doping on the Optoelectronic and Microstructural Properties 20 1.5 TiO2 Thin Films and Their Various Applications 21 1.5.1 In the Photovoltaic Field 21 1.5.2 In the Gas Sensors Field 22 1.5.3 In the Photocatalysis Field 23 1.5.4 TiO2 Photocatalytic Operating Mode 24 References 25 2 Synthesis and Characterization of TiO2–Cr Thin Films 27 Abstract 27 2.1 Synthesis of Thin Films by Magnetron Sputtering 27 2.1.1 The Thin Film Formation Steps 28 2.1.1.1 Classification of the Growth Modes 28 2.1.1.2 The Morphology of Thin Films 28 2.1.2 Principle of Operation 29 2.1.2.1 Description of the Deposition Machine 29 2.1.2.2 Deposition Requirements for the Development of Cr-Doped TiO2 Thin Films 29 2.1.2.3 Drawbacks and Benefits 29 2.1.2.4 Conclusion 30 2.2 Electroetching 30 2.2.1 Cell Anodizing 30 2.2.2 Development of the PS Layers 31 2.3 Microstructural and Analytical Characterization 31 2.3.1 X-ray Photoelectron Spectroscopy (XPS) 32 2.3.2 Infrared Fourier Transform Spectroscopy (FTIR) 32 2.3.3 Grazing Incidence X-ray Diffraction (GIXRD) 33 2.3.4 X-ray Reflectometry (XRR) 33 2.3.5 Atomic Force Microscopy (AFM) 33 2.3.6 Scanning Electron Microscope (SEM) 35 2.3.7 Photoluminescence Setup 36 2.4 Electrical and Optoelectronic Characterizations 36 2.4.1 Test of Gas Sensors 36 2.4.2 Light Beam Induced Current Technique (LBIC) 37 2.4.3 Quantum Efficiency 39 2.5 Optical Characterisations 40 2.5.1 UV-Visible Spectrometer 40 2.5.2 Ellipsometry 41 2.6 Conclusion 44 References 44 3 Microstructure and Optical Properties of Pure and Cr-Doped TiO2 Thin Films 46 Abstract 46 3.1 Introduction 46 3.2 Effect of Cr Concentration 47 3.2.1 Structural Properties 47 3.2.1.1 XPS Analysis of TiO2 Films 47 3.2.1.2 Analysis by X-ray Diffraction (XRD) 49 3.2.1.3 Analysis of the Film Density by X-ray Reflectometry 49 3.2.1.4 Analysis by Fourier Transform Infra-Red Spectroscopy (FTIR) 52 3.2.1.5 Raman Spectroscopy Analysis 52 3.2.1.6 Films Morphology: Analysis by Atomic Force Microscopy 53 3.2.1.7 Observation by Scanning Electron Microscopy (SEM) 53 3.2.2 Optical Properties 54 3.2.2.1 Optical Analysis by Ellipsometry 54 3.2.2.2 Analysis by UV-Visible Spectroscopy 56 3.3 Annealing Effect 58 3.3.1 Structural Properties 58 3.3.1.1 X-ray Diffraction 58 3.3.1.2 X-ray Reflectometry 59 3.3.1.3 Analysis by Fourier Transform Infrared Spectroscopy (FTIR) 60 3.3.1.4 Analysis by Raman Spectroscopy 61 3.3.1.5 Films Morphology: Analysis by Atomic Force Microscopy 61 3.3.1.6 Observation by Scanning Electron Microscopy (SEM) 61 3.3.2 Opticals Properties 62 3.3.2.1 Optical Analysis by Ellipsometry 62 3.3.2.2 Transmission 65 3.4 Conclusion 65 References 66 4 Gas Sensors and Photo-Conversion Applications 68 Abstract 68 4.1 Introduction 68 4.2 Detection Properties of Cr Doped TiO2 Films for Ethanol 69 4.2.1 Tests Under Ethanol 69 4.2.2 Electrical Characterizations Under Ethanol 70 4.2.3 Conductance Measurement 70 4.2.4 Sensitivity 71 4.2.5 The Response and Recovery Time Measurement 73 4.2.6 Effect of Cr Content on the Conductance Behavior 73 4.3 Nano-Composite TiO2Porous Si and Photoluminescence 75 4.3.1 Microstructural and Optoelectronic Analysis TiO2–CrSi–PorousSi Monocrystalline Films 75 4.3.1.1 Morphology of Layers: Analysis by Atomic Force Microscopy 75 4.3.1.2 Reflectivity 76 4.3.1.3 Photoluminescence 76 4.3.1.4 LBIC Measurements 77 4.3.2 Microstructural and Optoelectronics Analysis of the TiO2–CrPorous Multicrystalline Si Films 78 4.3.2.1 Layers Morphology: Analysis by Atomic Force Microscopy 78 4.3.2.2 Layers Morphology: Analysis by Scanning Electron Microscope 78 4.3.2.3 Reflectivity 80 4.3.2.4 Lifetime 80 4.3.2.5 The Diffusion Length 83 4.3.2.6 Local Characterisation at the Level of the Grains Joint 83 4.4 Conclusion 83 References 84 5 TiO2 Photocatalysis 86 Abstract 86 5.1 Introduction 86 5.2 Part A: Photocatalytic Activity of Cr-Doped TiO2 Thin Films Deposited on PS Substrates 87 5.2.1 Microstructural Analysis of TiO2–CrPSc-Si 87 5.2.1.1 X-ray Diffraction 87 5.2.1.2 Photocatalytic Application 88 5.3 Part B: Photocatalytic Activity of Cr-Doped TiO2 Thin Films Deposited on Quartz Substrates 90 5.3.1 Optical Analysis TiO2–CrQuartz Substrate 90 5.3.1.1 Urbach Energy and Absorption Coefficient 90 5.3.1.2 Photocatalytic Application 91 5.4 Conclusion 94 References 95 Conclusion 96 Front Matter....Pages i-xiii TiO 2 Properties and Deposition Techniques....Pages 1-14 Synthesis and Characterization of TiO 2 –Cr Thin Films....Pages 15-33 Microstructure and Optical Properties of Pure and Cr-Doped TiO 2 Thin Films....Pages 35-56 Gas Sensors and Photo-Conversion Applications....Pages 57-74 TiO 2 Photocatalysis....Pages 75-84 Back Matter....Pages 85-86