Title Page
ABSTRACT
국문 초록
PREFACE
Contents
NOMENCLATURE 16
CHAPTER 1. INTRODUCTION 19
1.1. Basic Theory of Si Solar Cells 19
1.2. Tunnel Oxide Passivating Contact(TOPCon) Solar Cells 22
1.3. Carrier Selctive Contact Layer of Solar Cells 25
1.4. Measurement Methods 28
1.4.1. Transmission Electron Microscopy (TEM) and Energy Dispersive X-Ray Spectroscopy (EDS) 28
1.4.2. X-Ray Photoelectron Spectroscopy (XPS) and Ultraviolet Photoelectron Spectroscopy (UPS) 29
1.4.3. Quasi-Steady-State Photoconductance (QSSPC) 30
CHAPTER 2. TUNNEL OXIDE PASSIVATING CONTACT REAR EMITTER (TOPCoRE) SOLAR CELLS WITH HOLE-SELECTIVE LAYER 32
2.1. Molybdenum Oxide Hole-Selective Contact 32
2.2. Power Loss and Current Path of n-TOPCon and p-TOPCoRE Solar Cells 34
2.3. Concept of the p-TOPCoRE with Front Local MoOx Contact Cells[이미지참조] 38
CHAPTER 3. EXPERIMENTAL METHODS AND RESULTS 41
3.1. Fabrication Process of the Cells 41
3.2. Properties of MoOx Layer[이미지참조] 44
3.2.1. Effect of Work Function of Front Contacts 44
3.2.2. TEM and EDS Analysis 48
3.2.3. XPS and UPS Analysis 52
3.2.4. Passivation and Contact Resistance 62
3.3. Passivation Properties of Front and Rear Side Structures 67
3.3.1. Hydrogenation Passivation 67
3.3.2. Front MoOx Local Contact Structure[이미지참조] 70
3.3.3. Rear Emitter Structure 73
3.3.4. Cell-Like Structure 76
3.4. Cell Performance and Loss Analysis 79
3.4.1. I-V Characteristics and Quantum Efficiency 79
3.4.2. Simulation of TOPCoRE with MoOx Solar Cells[이미지참조] 86
CHAPTER 4. CONCLUSION 90
REFERENCES 91
Table 1. Previous research of hole-selective contact 27
Table 2. Core energy level peaks of Mo3d with various thickness 56
Table 3. Results of light I-V data 82
Table 4. Results of Dark I-V data 83
Table 5. Parameters of Suns-Voc data[이미지참조] 84
Figure 1. Schematic diagram of operating principle for solar cell 21
Figure 2. Cell structure of (a) n-TOPCon, (b) p-TOPCoRE 24
Figure 3. Power loss analysis of n-FJ, p-BJ(1), p-BJ(10) 36
Figure 4. Current path simulation results of front and rear junction cells 37
Figure 5. Structure of the p-TOPCoRE with front local MoOx contact solar cells[이미지참조] 39
Figure 6. Band structure of p-TOPCoRE with front local MoOx contact solar cells[이미지참조] 40
Figure 7. Schematic of the fabrication flow of the p-TOPCoRE with front local MoOx contact solar cells[이미지참조] 43
Figure 8. Energy of the p-Si/MoOx interface with various work function of MoOx film[이미지참조] 47
Figure 9. TEM images of Ag/MoOx /SiOx /p-Si structure with different MoOx thickness (a) 5 n m, (b) 10 nm, (c) 15 nm, (d) 20 nm[이미지참조] 50
Figure 10. EDS line mapping data through the TEM images with MoOx thickness (a) 5 nm, (b) 10 nm, (c) 15 nm, (d) 20 nm 51
Figure 11. XPS analysis of MoOx thin film with various thickness of 5~20 nm[이미지참조] 55
Figure 12. UPS spectra of MoOx film with various thickness of 5~20nm (a) work function fitting, (b) valance band region, (c) Band bending calculation[이미지참조] 57
Figure 13. XPS depth profiling results: As deposition 58
Figure 14. XPS depth profiling of MoOx : After Annealing (a) O₂, (b) Forming gas atmosphere[이미지참조] 59
Figure 15. UPS measurement data of As dep., O₂, FGA samples 60
Figure 16. Work function of MoOx film by KPFM measurement with various annealing conditions[이미지참조] 61
Figure 17. Implied Voc results with (a) various thickness, (b) various temperature of 15 nm thick[이미지참조] 65
Figure 18. (a) Contact resistance and (b) I-V curve of Ag/MoOx /p-Si[이미지참조] 66
Figure 19. Schematic of the hydrogenation passivation using single and stack layer 69
Figure 20. Passivation properties of front side symmetric structures, finger region information and schematic (left), iVoc data (right) 72
Figure 21. Passivation properties of rear side symmetric structures, iVoc of the SDE and TEX surfaces via process steps (left), △iVoc of different post annealing temperatures 75
Figure 22. Schematic of the various front surface passivation structures (left) and iVoc of the various cell-like structures 78
Figure 23. Light I-V curve of various MoOx thickness[이미지참조] 82
Figure 24. Dark I-V curve of various MoOx thickness[이미지참조] 83
Figure 25. EQE, IQE, R% results of cells with various MoOx thickness[이미지참조] 85
Figure 26. Improvement of cell parameters by changing front characteristics 88
Figure 27. Simulation results of the p-TOPCoRE with the front local MoOx contact structure under the ideal conditions[이미지참조] 89