Contents
Abstract (in Chinese)
Abstract (in English)
Table Captions
Figure Captions
Chapter 1 Introduction 1
1.1 Review of Gallium-Nitride (GaN)-Based Light-Emitting Diodes (LEDs) 1
1.2 Brief History of GaN-Based LEDs 3
1.3 Organization of this Dissertation 5
Chapter 2 Improved Current-Spreading Characterizations of GaN-Based LEDs by Epitaxial Technique 8
2.1 GaN LEDs with P-GaN/Undoped InGaN Superlattice Structure 9
2.1.1 Motivation 9
2.1.2 Experimental Results 12
2.1.3 A Current-Spreading Model 13
2.1.4 Material Analyses 14
2.1.5 Electrical and Optical characteristics 17
2.1.6 Summary 23
2.2 GaN LEDs with a p-GaN/n-GaN Energy Barrier Junction 23
2.2.1 Motivation 24
2.2.2 Experimental Details 26
2.2.3 Material Analyses and Schematic Energy-Band Diagram 28
2.2.4 Electrical and Optical Characteristics 29
2.2.5 Junction Temperature Analyses 34
2.2.6 ESD Measurements 35
2.2.7 Reliability 37
2.2.8 Summary 37
Chapter 3 Improved Current-Spreading Performance of GaN-Based LEDs by Au Thermal-Diffused and Removed Processes 39
3-1 Motivation 39
3-2 Experimental Details 41
3-3 Material Analyses 43
3-4 Optical and Electrical Characteristics 46
3-5 Summary 48
Chapter 4 GaN LEDs Grown on c-Toward m-Plane Misoriented Sapphire Substrates 50
4-1 Performance Investigation of GaN LEDs Grown on Mis-Oriented Sapphire Substrates 51
4.1.1 Motivation 51
4.1.2 Experimental Details 54
4.1.3 Material Quality Analyses 56
4.1.4 Turn-On Voltage versus AFM Results 58
4.1.5 Current-Voltage (I-V) Characteristics 59
4.1.6 Ideality Factors 61
4.1.7 Capacitance-Voltage (C-V) Measurements 62
4.1.8 Optical Properties 64
4.1.9 Summary 66
4-2 ESD Characteristics of GaN LEDs Grown on Mis-Oriented Sapphire Substrates 67
4.2.1 Motivation 67
4.2.2 Experimental Details 69
4.2.3 Dislocation Density Analyses 72
4.2.4 The Origin of Maximum Capacitance (Cm) and the Relation between Cm and ESD Endurance of LEDs 73
4.2.5 Surface Morphology Characterizations of LEDs 79
4.2.6 ESD Performance of LEDs 81
4.2.7 Summary 84
Chapter 5 Conclusion and Prospects 85
5.1 Conclusion 85
5.2 Prospects 88
References 91
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