1. Crystal Growth of III/V Semiconductor Nanowires Kobi Greenberg

2. Metal organic molecular beam epitaxy (MOMBE)

3. Future applications of nanowires Martensson et al Nanowire LED Maarten et al Single photon emitter Algra et al Crystal structure engineering Nanowires as a Biological Interface Mårtensson et al

4. The vapor liquid solid growth mechanism TMI 420 o C In P2P2 Au catalyst InP

5. TEM pictures of InP nanowires grown in our lab by the vapor liquid solid method ZB WZ Au InP

6. Two ways to arrange cannon balls Cubic structure Hexagonal structure

7. Stacking fault formation A B C A B C A B A B A B Zincblende nanowireWurzite nanowire With stacking fault A B C B A B SF

8. Limitations of the vapor liquid solid method Difficult to eliminate stacking fault Very sensitive to wafer surface effects Calahorra, Greenberg et al. nanotechnology 2012 TMI 420 o C In P2P2 Au catalyst InP

9. The selective area vapor liquid solid growth method Si 3 N 4 Dalacu et al, Nanotechnology 2009 Au catalyst TMI 420 o C P2P2

10. TEM pictures of InP nanowires grown in our lab by selective area vapor liquid solid method: no stacking faults

11. Advantages of the selective area vapor liquid solid method Easy to eliminate stacking fault in InP nanowires not sensitive to wafer surface effects Predictable growth rate Si 3 N 4 Au catalyst TMI 420 o C P2P2

12. Fabrication Wafer cleaning Si 3 N 4 deposition Electron sensitive resist coating Electron beam lithography + development+ BOE InP B substrate

13. Gold evaporation Lift off

14. nanowire heterostuctures: important for device applications conventional layers of materials having different lattice constant cannot be grown on top of each other as single crystals. Due to their small dimensions, a stack of materials with different lattice constants can be grown as a single crystal GaP InGaP

15. Heterostructure analysis by EDX and STEM HAADF 1 2 3 12 3 3

16. Summary Selective area vapor liquid solid is the method of choice for defect free nanowire growth. Heterostructures of InP and GaP having 7.7% lattice mismatch were demonstrated. Method will be implemented for other materials such as GaAs, GaP,InAs and their heterostuctures.