Preparation of oriented cadmium sulfide nanocrystals

Abstract

Cadmium sulfide (CdS) particulate films, composed of highly oriented, rod-like nanocrystals have been generatedin situ by the exposure of stearic acid (SA) Langmuir monolayer-coated aqueous CdCl₂ solutions to hydrogen sulfide (H₂S). The SA-coated CdS particulate films were transferred to a solid substrate and examined by transmission electron microscopy (TEM) and Auger electron energy spectroscopy. It was found for the first time that the electron diffraction pattern was a composite one with six sets of diffraction patterns which were contributed by the different oriented CdS nanocrystals in these particulate films system. The epitaxial growth of rod-like CdS nanocrystals has been rationalized in terms of matching the d₂₂₀ spacing of the cubic CdS crystals and the d_101̄0 spacing of the hexagonal closed-packed SA monolayer. The presence of a negatively charged monolayer at the air/water interface was an essential requirement for the oriented growth of CdS nanocrystals. This leads to a novel means of fabrication of highly oriented semiconductor quantum wires.

References

1. L. E. Brus, IEEE J. Quantum Electron., 1986, 22, 1909.
2. R. R. Chandler and J. L. Coffer, J. Phys. Chem., 1993, 97, 9767.
3. H. Weller, Angew. Chem., Int. Ed. Engl., 1993, 32, 41.
4. A. Mews, A. Eychmuller, M. Giersig, D. Schooss and H. Weller, J. Phys. Chem., 1994, 98, 934.
5. Y. Wang and N. Herron, J. Phys. Chem., 1991, 95, 525.
6. H. Weller, Adv. Mater., 1993, 5, 88.
7. Y. Wang and N. Herron, Phys. Rev. B, 1992, 42, 42.
8. L. Blus, Appl. Phys. A, 1991, 53, 465.
9. V. L. Clvin, A. N. Goldstein and A. P. Alivisatos, J. Am. Chem. Soc., 1992, 114, 5221.
10. J. R. Heath, Science, 1995, 270, 1315; C. B. Murray, C. R. Kagan and M. G. Bawendi, Science, 1995, 270, 1335.
11. C. R. Martin, Science, 1994, 266, 1961.
12. S. Mann, Nature (London), 1993, 365, 499.
13. I. Meriguchi, I. Tanaka, Y. Teraoka and S. Kagawa, J. Chem. Soc., Chem. Commun., 1991, 1401.
14. X. K. Zhao, Y. Yuan and J. H. Fendler, J. Chem. Soc., Chem. Commun., 1990, 1248.
15. X. K. Zhao, L. D. McCormick and J. H. Fendler, Chem. Mater., 1991, 3, 922.
16. X. K. Zhao and J. H. Fendler, Chem. Mater., 1991, 3, 168.
17. X. K. Zhao, S. Q. Xu and J. H. Fendler, Langmuir, 1991, 7, 520.
18. X. K. Zhao, L. D. McCormick and J. H. Fendler, Langmuir, 1991, 7, 1255.
19. X. K. Zhao and J. H. Fendler, J. Phys. Chem., 1991, 95, 3716.
20. X. K. Zhao and J. H. Fendler, J. Phys. Chem., 1992, 96, 9933.
21. J. Yang, J. H. Fendler, T. C. Jao and T. Laurion, Microsc. Res. Tech., 1994, 27, 402.
22. B. R. Heywood, S. Rajam and S. Mann, J. Chem. Soc., Faraday Trans., 1991, 87, 727; 735.
23. B. R. Heywood and S. Mann, J. Am. Chem. Soc., 1992, 114, 4681.
24. G. P. Luo, Z. M. Ai, J. J. Hawkes, Z. H. Lu and Y. Wei, Phys. Rev. B, 1993, 48, 15337 and refs. therein.
25. Z. Y. Pan, X. G. Peng, Z. H. Wu, T. J. Li, M. Zhu and J. Z. Liu, Langmuir, 1996, 12, 851.
26. Z. Y. Pan, X. G. Peng, T. J. Li and J. Z. Liu, Chin. J. Sci. Instrum., 1996, 17, 153.
27. V. K. Gupta, J. A. Kornfield, A. Ferencz and G. Wegner, Science, 1994, 265, 940.
28. A. P. Alivisatos, MRS Bull., 1995, XX, 23.
29. O. Osugi et al., Rev. Phys. Chem. Jpn., 1966, 36, 59; Joint Committee on Power Diffraction Stands, 1971.
30. J. B. Peng and G. T. Barnus, Thin Solid Films, 1994, 252, 44.
31. R. Viswanathan, L. L. Madsen, J. A. Zasadzinski and D. K. Schwartz, Science, 1995, 269, 51.
32. Auger Electron Spectra Catalogue, A Data Collection of Elements, Anelva Corporation, 1979.
33. Y. Wang, Acc. Chem. Res., 1991, 24, 133.