Hostname: page-component-848d4c4894-2xdlg Total loading time: 0 Render date: 2024-06-23T22:47:08.691Z Has data issue: false hasContentIssue false

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

Published online by Cambridge University Press:  15 February 2011

G. Morell
Affiliation:
Dept. of Physics, Univ. of Puerto Rico, Box 23343, San Juan, PR 00931
R. S. Katiyar
Affiliation:
Dept. of Physics, Univ. of Puerto Rico, Box 23343, San Juan, PR 00931
S. Z. Weisz
Affiliation:
Dept. of Physics, Univ. of Puerto Rico, Box 23343, San Juan, PR 00931
H. Jia
Affiliation:
Ames Laboratory - USDOE and Department of Physics & Astronomy, Iowa State University, Ames, Iowa 50011, USA
J. Shinar
Affiliation:
Ames Laboratory - USDOE and Department of Physics & Astronomy, Iowa State University, Ames, Iowa 50011, USA
I. Balberg
Affiliation:
Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
Get access

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.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Beeman, D., Tsu, R. and Thorpe, M.F., Phys. Rev. B 32, 874 (1985).Google Scholar
2. Maley, N., Beeman, D. and Lannin, J.S., Phys. Rev. B 38, 10611 (1988).Google Scholar
3. Muller, G. and Krötz, G., Mater. Res. Soc. Symp. Proc. 297, 237 (1993).Google Scholar
4. Schubert, M.B. and Bauer, G.H., Proc XXI IEEE PVSE, 1595 (1990).Google Scholar
5. Ranchoux, B. et al, J. Non-Cryst Solids 53 & 60, 185 (1983).Google Scholar
6. Tsu, R. et al, Solid State Comm 46, 79 (1983).Google Scholar
7. Hishikawa, Y. et al, Appl Phys Lett 57, 771 (1990).Google Scholar
8. Bhattacharyya, T.K., Chaudhuri, P., and Banerjee, R., J. Appl Phys B 74, 3211 (1993).Google Scholar
9. Singh, J., Phys Rev B 23, 4156 (1981).Google Scholar
10. Kohyama, M. and Yamamoto, R., Mater. Res. Soc. Symp. Proc. 297, 177 (1993).Google Scholar
11. Tsu, R., Hernández, J.G., and Poliak, F.H., J. Non-Cryst 66, 109 (1984).Google Scholar
12. Mahan, A.H. et al, J. Appl. Phys. 69, 6728 (1991).Google Scholar
13. Moustakas, T.D., Tiedje, T., Lanford, W.A., Tetra Bond Amorph Sernic AIP Proc 73, 20 (1981)Google Scholar
14. Moddel, G. et al, TeÍrahedrally Bonded Amorphous Semicond AIP Conf Proc 73, 25 (1981).Google Scholar
15. Jousse, C. et al, J. Non-Cryst Solids 77 & 78, 627 (1985).Google Scholar
16. Farias, M.H. et al, Mater. Res. Soc. Symp. Proc. 336, 425 (1994).Google Scholar
17. Moreli, G. et al, Mater. Res. Soc. Symp. Proc. 297, 321 (1993).Google Scholar
18. Alben, R., Weaire, D., Smith, J.E., and Brodsky, M.H., Phys Rev B 11, 2271 (1975).Google Scholar
19. Tsu, R., J. Non-Cryst Solids 114, 199 (1989).Google Scholar
20. Sokolov, A.P. and Shebanin, A. P., Sov Phys Semicond 24, 720 (1990).Google Scholar
21. Kshirsagar, S.T. and Lannin, J.S., Phys Rev B 25, 2916 (1982).Google Scholar
22. Brodsky, M.H., Cardona, M., and Cuomo, J.J., Phys Rev B 15, 3556 (1977).Google Scholar
23. Bermejo, D. and Cardona, M., J. Non Cryst. Solids 32, 405 (1979).Google Scholar
24. Li, Y.-M., Fieselmann, B.F., Catalano, A., Proc XXII IEEE PVSC, 1231 (IEEE, NY, 1991)Google Scholar
25. Mitra, S. et al, Phys. Rev. B, 48 2175 (1993).Google Scholar
26. Moreli, G. et al, Mater. Res. Soc. Symp. Proc. 336, 607 (1994).Google Scholar
27. Zellama, K. et al, J. Non-Cryst Sol, 164–166 285 (1993).Google Scholar
28. Beyer, W., Wagner, H., and Finger, F., J. Non-Cryst Solids 77 & 78, 857 (1985).Google Scholar
29. Berntsen, A.J.M. et al, Phys Rev B 48, 14656 (1993); Mater Res Soc Proc 297, 303 (1993).Google Scholar