Chapter 1 Introduction
1.1 Solar energy
1.2 Solar cell operation
1.2.1 Photovohaic effect
1.2.2 Band discontinuity at heterojunction interface
1.3 Photovoltaic material research
1.4 Background and survey of literature of Cu2ZnSnS4-based solar cells
1.4.1 Properties of Cu2ZnSnS4 thin films
1.4.2 CdS/CZTS heterointerfaces
1.4.3 ZnO/CZTS heterointerface
1.4.4 Secondary phases in kesterite Cu2ZnSnS4 absorber thin film
1.5 First-principles calculation
1.5.1 Density functional theory (DFT)
1.5.2 Exchange-Correlation functional approximations
1.5.3 Pseudopotential
1.6 Objective of this work
1.7 Preview of the monograph
References
Chapter 2 Prediction of the Band Offsets at the CdS/Cu2ZnSnS4 Interface Based on the First-Principles Calculation
2.1 Introduction
2.2 Calculation
2.2.1 Structure of CdS/CZTS heterojunction
2.2.2 Calculation of density of states
2.3 Results and discussion
2.3.1 Calculation of energy levels and predicted VBM positions for the respective layer of atom in the CdS/Cu2ZnSnS4 supercell
2.3.2 Band alignment at the CdS/Cu2ZnSnS4 heterointerface
2.3.3 Charge of each atom for the respective layers in the supercell
2.4 Conclusion
References
Chapter 3 Influences of Crystal Structure and Orientation on Band Offsets at the CdS/Cu2ZnSnS4 Interface
3.1 Introduction
3.2 Calculation
3.2.1 Structure of CdS/CZTS heterojunetion
3.2.2 Calculation of density of states
3.3 Results and discussion
3.3.1 Energies of the reference core levels and VBM for the respective layer
3.3.2 Charge of each atom
3.3.3 Band alignment at the CdS/Cu2ZnSnS4 heterointerfaee
3.4 Conclusion
References
Chapter 4 Band Offsets at the ZnO/Cu2ZnSnS4 Interface Based on the First Principles Calculation
4.1 Introduction
4.2 Calculation
4.2.1 ZnO/CZTS heterostructure
4.2.2 Density of states
4.3 Results and discussion
4.3.1 Effects of interface atomic structure
4.3.2 Effects of strain and the conduction band offset
4.3.3 Consequences with the solar cell properties
4.4 Conclusions
Referanees
Chapter 5 Influence of Secondary Phases in Kesterite-Cu2ZnSnS4 Absorber Material
5.1 Introduction
5.2 Calculation
5.2.1 Crystal structure of CH2SnS3
5.2.2 Density of state
5.3 Result and discussion
5.4 Conclusion
References
Chapter 6 Band Offsets Engineering at CdxZn1-xS/Cu2ZnSnS4 Heterointerface
6.1 Introduction
6.2 Calculation
6.3 Results and discussions
6.3.1 Electronic structures and band gap
6.3.2 Band alignment for Cd1-xZnxS/CZTS heterointerfaces
6.4 Conclusion
References
Chapter 7 Study of Band Offset at ZnS/CueZnIVS4 (IV = Si, Ge, Sn) Heterointerfaces
7.1 Introduction
7.2 Calculation
7.3 Result and discussion
7.3.1 First principles calculation
7.3.2 Numerical simulation
7.4 Conclusion
References
Chapter 8 Conclusions
8.1 Main conclusion of this monograph
8.2 Suggestions for future work
Publications