Title Page
Abstract
Contents
1. Introduction 10
1.1. Van der Waals(vdW) layered structures of PbI₂ and SnS 10
1.2. vdW mixed dimensional heterostructure 13
2. Research 15
2.1. Experimental Details 15
2.1.1. Growth of PbI₂ nanowires 15
2.1.2. Growth of SnS flakes 16
2.1.3. Fabrication of PbI₂/SnS heterostructure 16
2.1.4. Characterization 16
2.2. Results & Discussion 19
2.3. Conclusion 27
References 44
Figure 1. Self-catalyzed Vapor-Liquid-Solid growth of PbI₂ nanowires. 11
Figure 2. Optimized structures of monolayers of group-IV monochalcogenides with phosphorenelike structure. 12
Figure 3. Two-dimensional layered materials and van der Waals heterostructures. 14
Figure 4. Schematics of the experimental procedure. 18
Figure 5. PbI₂ nanowire - SnS flake heterostructures. 28
Figure 6. TEM analysis of SnS flake. 29
Figure 7. TEM analysis of PbI₂ nanowire. bright-field TEM images. 30
Figure 8. Thickness/width ration with different growth direction of PbI₂ nanowire. 31
Figure 9. Cross-sectional analysis of PbI₂/SnS heterostructure. 32
Figure 10. PbI₂ and SnS interlayer spacing. 33
Figure 11. Orientation-dependent Raman spectroscopy and PL spectroscopy of PbI₂/SnS heterostructures. 34
Figure 12. Raman spectrum of PbI₂ nanowires. 35
Figure 13. SnS flake Raman spectra of PbI₂/SnS heterostructures. 36
Figure 14. Photoluminescence (PL) analysis of bare [001]-PbI₂ and [010]-PbI₂ nanowires 37
Figure 15. Effect of temperature on the heterointerfacial exitonic emission. 38
Figure 16. Variation in the excitonic emission according to the substrate material and PbI₂ nanowire directions. 39
Figure 17. Substrate-dependent CL luminescence coverage calculated using imageJ. 40
Figure 18. AFM analysis of SnS flake and bare Si(100) wafer. 41
Figure 19. Varshni relation fitting of CL point spectrum. 42
Figure 20. Arrhenius function fitting of CL point spectrum. 43