Nanoscale Microwave Engineering: Optical Control of Nanodevices

INTRODUCTION ix

CHAPTER 1. NANOTECHNOLOGY-BASED MATERIALS AND THEIR INTERACTION WITH LIGHT 1

1.1. Review of main trends in 3D to 0D materials 1

1.1.1. Main trends in 3D materials for radio frequency (RF) electronics and photonics 1

1.1.2. Main trends in 2D materials for RF electronics and photonics 2

1.1.3. Review of other two-dimensional structures for RF electronic applications 5

1.1.4. Main trends in 1D materials for RF electronics and photonics 6

1.1.5. Other 1D materials for RF applications 9

1.1.6. Some attempts on 0D materials 13

1.2. Light/matter interactions 13

1.2.1. Fundamental electromagnetic properties of 3D bulk materials 14

1.2.2. Linear optical transitions 22

1.2.3. Bandgap engineering in nanomaterials: effect of confinement/sizing on bandgap structure 23

1.3. Focus on two light/matter interactions at the material level 26

1.3.1. Photoconductivity in semiconductor material 26

1.3.2. Example of light absorption in metals: plasmonics 45

CHAPTER 2. ELECTROMAGNETIC MATERIAL CHARACTERIZATION AT NANOSCALE 51

2.1. State of the art of macroscopic material characterization techniques in the microwave domain with dedicated equipment 51

2.1.1. Static resistivity 51

2.1.2. Carrier and doping density 53

2.1.3. Contact resistance and Schottky barriers 55

2.1.4. Transient methods for the determination of carrier dynamics 56

2.1.5. Frequency methods for complex permittivity determination in frequency 57

2.2. Evolution of techniques for nanomaterial characterization 60

2.2.1. The CNT transistor 60

2.2.2. Optimizing DC measurements 60

2.2.3. Pulsed I-V measurements 61

2.2.4. Capacitance–voltage measurements 61

2.3. Micro- to nanoexperimental techniques for the characterization of 2D, 1D and 0D materials 62

CHAPTER 3. NANOTECHNOLOGY-BASED COMPONENTS AND DEVICES 65

3.1. Photoconductive switches for microwave applications 67

3.1.1. Major stakes 67

3.1.2. Basic principles 67

3.1.3. State of the art of photoconductive switching 71

3.1.4. Photoconductive switching at nanoscale – examples 72

3.2. 2D materials for microwave applications 74

3.2.1. Graphene for RF applications 74

3.2.2. Optoelectronic functions 76

3.2.3. Other potential applications of graphene 77

3.3. 1D materials for RF electronics and photonics 78

3.3.1. Carbon nanotubes in microwave and RF circuits 78

3.3.2. CNT microwave transistors 79

3.3.3. RF absorbing and shielding materials based on CNT composites 82

3.3.4. Interconnects 83

CHAPTER 4. NANOTECHNOLOGY-BASED SUBSYSTEMS 85

4.1. Sampling and analog-to-digital converter 85

4.1.1. Basic principles of sampling and subsampling 87

4.1.2. Optical sampling of microwave signals 89

4.2. Photomixing principle 89

4.3. Nanoantennas for microwave to THz applications 91

4.3.1. Optical control of antennas in the microwave domain 91

4.3.2. THz photoconducting antennas 91

4.3.3. 2D material-based THz antennas 92

4.3.4. 1D material-based antennas 92

4.3.5. Challenges for future applications 96

CONCLUSIONS AND PERSPECTIVES 99

C.1. Conclusions 99

C.2. Perspectives: beyond graphene structures for advanced microwave functions 100

C.2.1. van der Waals heterostructures 101

C.2.2. Beyond graphene: heterogeneous integration of graphene with other 2D semiconductor materials 103

C.2.3. Graphene allotropes 103

BIBLIOGRAPHY 105

INDEX 119