Tunable Plasmonic Metamaterial

A Dissertation by

Mehdi Keshavarz Hedayati

Submitted to the Faculty of Engineering of Christian-Albrechts-Universitat zu Kiel in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY

February 2014

http://d-nb.info/105959272X Contents

Acknowledgements X

1 Abstract 1

2 Introduction 3 2.1 Materials for energy 3 2.2 Plasmonic and Metamaterial 4 2.3 Metamaterial absorbers 6 2.3.1 Resonant (narrowband) perfect absorbers 7 2.3.2 Broadband (multi-band) perfect absorbers 10 2.3.3 Switchable metamaterial perfect absorbers 14 2.4 Antireflective coating (ARC) 15 2.4.1 Structured surface as ARC 15 2.4.2 Gradient film (structure) as ARC 16 2.5 Introduction of thesis 20

3 Materials and Methods 23 3.1 Materials 23 3.1.1 Targets 23 3.1.2 Substrates 24 3.2 Metal and nanocomposite film preparation 24 3.2.1 Cleanroom specifications 24 3.2.2 Magnetron sputtering chamber specifications 24 3.2.3 Metallic film deposition 25 3.2.4 Dielectric film deposition 26 3.2.5 Nanocomposite deposition 26

XV XVI Contents

3.2.6 Rate determination 26 3.2.7 Spin-coating 27 3.3 Characterizations 27 3.3.1 Profilometer 27 3.3.2 Ultraviolet-visible spectroscopy 28 3.3.3 Spectroscopic Ellipsometry 28 3.3.4 Transmission Electron Microscopy 28 3.3.5 Energy Dispersive X-ray spectroscopy 29

4 Review of plasmonic nanocomposite metamaterial absorber 30 4.1 Abstract 30 4.2 Introduction 31 4.2.1 Plasmons and plasmonics 31 4.2.2 Energy and metals 31 4.2.3 Highly absorber structures: metal nanostructure and films 32 4.2.4 Theoretical consideration 35 4.3 Metal-dielectric nanocomposites with tailored plasmonic response 36 4.3.1 Fabrication procedure 37 4.3.2 Results and Discussion 38 4.3.3 Gold nanocomposite 38 4.3.4 Copper nanocomposite 40 4.3.5 Silver nanocomposite 44 4.4 Innovative design of light weight broadband nanocomposite perfect absorbers 47 4.5 Prospects and Future 50 4.6 Acknowledgments 51 4.7 Conflicts of Interest 51

5 Design of a perfect black absorber at visible frequencies using plasmonic metamaterials 52 5.1 Main text 52 5.2 Summary 57 5.3 Experimental 58 5.4 Acknowledgements 59 Contents XVII

6 Tunable broadband plasmonic perfect absorber at visible frequency 60 6.1 Abstract 60 6.2 Introduction 60 6.3 Experimental procedure 61 6.4 Results and discussion 61 6.5 Conclusions 65 6.6 Acknowledgements 65

7 Plasmonic tunable metamaterial absorber as ultraviolet protection film 66 7.1 Abstract 66 7.2 Introduction 66 7.3 Experimental Procedure 68 7.4 Results and Discussion 69 7.5 Conclusion 74 7.6 Acknowledgements 74

8 The hybrid concept for realization of an ultra-thin plasmonic metamaterial antireflection coating and plasmonic rainbow 76 8.1 Abstract 76 8.2 Introduction 76 8.3 Results and Discussion 78 8.4 Conclusion 85 8.5 Methods 85 8.5.1 Fabrication 85 8.5.2 Simulations 88 8.6 Acknowledgements 88

9 Photo-driven perfect absorber as active metamaterial with a tunable molecular- plasmonic coupling 89 9.1 Abstract 89 9.2 Main text 90 9.3 Summary 95 9.4 Acknowledgements 96 XVIII Contents

10 Summary and Outlook 97 10.1 (Passive) Metamaterials Perfect Absorber 97 10.2 Photoresponsive (Active) Perfect Absorber 98 10.3 Plasmonic antireflection coating 99 10.4 Outlook 99

Bibliography XXIV