Correlation Between Phototransport and Network Order in a-Si:H

Abstract

Hydrogenated amorphous silicon (a-Si:H) films prepared by the glow discharge (GD) technique show superior optoelectronic properties over those prepared by rf sputtering (RFS). To find out whether this is associated to structural differences in the amorphous network, we have carried out a comprehensive comparison of the Raman spectra of the two types of films grown at different substrate temperatures. The use of two properly chosen excitation radiations allowed the observation of the Raman spectra from the near surface versus that from the bulk of the films. The results show that the short-range order in the bulk of GD films is close to that of the ideal tetrahedral network, having an rms bond angle deviation (Δθ) of ≈9°. In contrast, the smallest value of Δθfound in the RFS films was ≈15°. There is also a short-range order inhomogeneity in both sets of materials that can be reduced significantly by selecting the appropriate substrate temperature. The intermediate-range disorder is relatively small and uniform in GD films, while large differences exist in this parameter between the surface and bulk of RFS films. In general, the results indicate that the short-range order and the inhomogeneity in intermediate-range order present in the RFS films cannot be improved to equal those of GD materials by annealing at temperatures low enough that no substantial hydrogen effusion occurs. These structural differences are argued to be the reasons for the superior phototransport properties of GD over RFS materials and are interpreted in terms of the differences between the two deposition processes.

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References

  1. 1.

    D. Beeman, R. Tsu and M.F. Thorpe, Phys. Rev. B 32, 874 (1985).

    CAS  Article  Google Scholar 

  2. 2.

    N. Maley, D. Beeman and J.S. Lannin, Phys. Rev. B 38, 10611 (1988).

    CAS  Article  Google Scholar 

  3. 3.

    G. Müller and G. Krötz, Mater. Res. Soc. Symp. Proc. 297, 237 (1993).

    Article  Google Scholar 

  4. 4.

    MB. Schubert and G.H. Bauer, Proc XXI IEEE PVSE, 1595 (1990).

  5. 5.

    B. Ranchoux et al, J. Non-Cryst Solids 53 & 60, 185 (1983).

    Article  Google Scholar 

  6. 6.

    R. Tsu et al, Solid State Comm 46, 79 (1983).

    CAS  Article  Google Scholar 

  7. 7.

    Y. Hishikawa et al, Appl Phys Lett 57, 771 (1990).

    CAS  Article  Google Scholar 

  8. 8.

    T.K. Bhattacharyya, P. Chaudhuri, and R. Banerjee, J. Appl Phys B 74, 3211 (1993).

    CAS  Article  Google Scholar 

  9. 9.

    J. Singh, Phys Rev B 23, 4156 (1981).

    CAS  Article  Google Scholar 

  10. 10.

    M. Kohyama and R. Yamamoto, Mater. Res. Soc. Symp. Proc. 297, 177 (1993).

    CAS  Article  Google Scholar 

  11. 11.

    R. Tsu, J.G. Hernández, and F.H. Pollak, J. Non-Cryst 66, 109 (1984).

    CAS  Article  Google Scholar 

  12. 12.

    A.H. Mahan et al, J. Appl. Phys. 69, 6728 (1991).

    CAS  Article  Google Scholar 

  13. 13.

    T.D. Moustakas,T. Tiedje, W.A. Lanford, Tetra Bond Amorph Semic AIP Proc 73, 20 (1981)

    CAS  Google Scholar 

  14. 14.

    G. Moddel et al, Teírahedrally Bonded Amorphous Semicond AIP Conf Proc 73, 25 (1981).

    CAS  Google Scholar 

  15. 15.

    C. Jousse et al, J. Non-Cryst Solids 77 & 78, 627 (1985).

    Article  Google Scholar 

  16. 16.

    M.H. Farias et al, Mater. Res. Soc. Symp. Proc. 336, 425 (1994).

    CAS  Article  Google Scholar 

  17. 17.

    G Morell et al, Mater. Res. Soc. Symp. Proc. 297, 321 (1993).

    Article  Google Scholar 

  18. 18.

    R Alben, D. Weaire, J.E. Smith, and M.H. Brodsky, Phys Rev B 11, 2271 (1975).

    CAS  Article  Google Scholar 

  19. 19.

    R. Tsu, J. Non-Cryst Solids 114, 199 (1989).

    CAS  Article  Google Scholar 

  20. 20.

    A.P. Sokolov and A. P. Shebanin, Sov Phys Semicond 24, 720 (1990).

    Google Scholar 

  21. 21.

    S.T. Kshirsagar and J.S. Lannin, Phys Rev B 25, 2916 (1982).

    CAS  Article  Google Scholar 

  22. 22.

    M.H. Brodsky, M. Cardona, and J.J. Cuomo, Phys Rev B 15, 3556 (1977).

    Article  Google Scholar 

  23. 23.

    D. Bermejo and M. Cardona, J. Non Cryst. Solids 32, 405 (1979).

    CAS  Article  Google Scholar 

  24. 24.

    Y.-M. Li, B.F. Fieselmann, A. Catalano, Proc XXII IEEE PVSC, 1231 (IEEE, NY, 1991)

    Google Scholar 

  25. 25.

    S. Mitra et al, Phys. Rev. B, 48 2175 (1993).

    CAS  Article  Google Scholar 

  26. 26.

    G. Morell et al, Mater. Res. Soc. Symp. Proc. 336, 607 (1994).

    Article  Google Scholar 

  27. 27.

    K. Zellama et al, J. Non-Cryst Sol, 164–166 285 (1993).

    Article  Google Scholar 

  28. 28.

    W. Beyer, H. Wagner, and F. Finger, J. Non-Cryst Solids 77 & 78, 857 (1985).

    Article  Google Scholar 

  29. 29.

    AIM. Berntsen et al, Phys Rev B 48, 14656 (1993); Mater Res Soc Proc 297, 303 (1993).

    CAS  Article  Google Scholar 

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Morell, G., Katiyar, R.S., Weisz, S.Z. et al. Correlation Between Phototransport and Network Order in a-Si:H. MRS Online Proceedings Library 377, 479–484 (1995). https://doi.org/10.1557/PROC-377-479

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