Hostname: page-component-77c89778f8-sh8wx Total loading time: 0 Render date: 2024-07-20T10:57:29.926Z Has data issue: false hasContentIssue false
  • English
  • Français

Why the Photoconductivity Decreases in a-SiC:H and a-SiGe:H when the Amount of Alloying Increases

Published online by Cambridge University Press:  26 February 2011

A. H. Mahan ,
P. Raboisson ,
P. Menna  and
R. Tsut
A. H. Mahan
Affiliation:
Solar Energy Research Institute, Golden, Colorado 80401
P. Raboisson
Affiliation:
Centre National de la Recherche Scientifique, Sophia Antipolis, F-6500 Valbonne, France
P. Menna
Affiliation:
ENEA/FARE-FOTO, C.P. 83, 80055 Portici, Italy
R. Tsut
Affiliation:
Electrical Engineering Dept., North Carolina A&T State Univ., Greensboro, N.C. 27411
Get access

Abstract

Infrared, photoconductivity, and photothermal deflection spectroscopy measurements have been used to probe the relationship between material quality and the amount of microstructure in glow discharge deposited a-SiC:H and a-SiGe:T films. We find that the microstructure is directly responsible for the decrease in photoconductivity observed in both alloys as a function of increased alloy content. The microstructure does this by causing a decrease in steepness of the Urbach tail, thus allowing for an increase in both carrier trapping at the wider band edges and carrier recombination at or near the band tails.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 95: Symposium E – Amorphous Silicon Semiconductors--Pure and Hydrogenated , 1987 , 361
Copyright
Copyright © Materials Research Society 1987

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

1. Kuwano, Y., Ohnishi, M., Nishiwaki, H., Tsuda, S., Fukatsu, T., Enomoto, K., Nakashima, Y. and Tarui, H., 16th IEEE PV Spec. Conference, San Diego (IEEE, New York, 1982), p. 1331.Google Scholar
2. Mahan, A. H., von Roedern, B., Williamson, D. L., and Madan, A., J. Appl. Phys. 57, 2717 (1985).Google Scholar
3. von Roedern, B., Mahan, A. H., McMahon, T. J. and Madan, A., Mater. Res. Soc. Symp. 49, 167 (1985).Google Scholar
4. Beyer, W., Wagner, H. and Finger, F., J. Non-Cryst. Sol. 77&78, 857 (1985).Google Scholar
5. Mahan, A. H., Raboisson, P. and Tsu, R., Appl. Phys. Lett. 50, 335 (1987).Google Scholar
6. Mahan, A. H., Raboisson, P., Williamson, D. L. and Tsu, R., Solar Cells 21 (1987) in press.Google Scholar
7. MacKenzie, K. D., Eggert, J. R., Leopold, D. J., Li, Y. M., Lin, S. and Paul, W., Phys. Rev. B 31, 2198 (1985).Google Scholar
8. Ichimura, B. T., Hama, T., Ihara, T., Ohsawa, M., Sakai, H. and Uchida, Y., 18th IEEE PV Spec. Conference, Las Vegas (IEEE, New York, 1985), p. 1495.Google Scholar
9. Menna, P., Mahan, A. H. and Tsu, R., to be published.11.Google Scholar
10. Skumanich, A., Frova, A. and Amer, N. M., Sol. St. Commun. 54, 597 (1985).Google Scholar
11. The absorption curves are given in reference EO. We have remeasured the Eo values, which are different from the values quoted in that paper.Google Scholar
12. Tsu, R., in Excitations in Disordered Systems, edited by Thorpe, M. F. (Plenum, New York, 1982) p. 623.Google Scholar
13. Tsu, R., Menna, P. and Mahan, A. H., Solar Cells 21 (1987), in press.Google Scholar
14. Tsu, R., Gonzalez-Hernandez, J., Doehler, J. and Ovshinsky, S. R., Solid State Commun. 46, 79 (1983).Google Scholar
15. Inoue, Y., Nakashima, S., Mitsuishi, A., Tabata, S. and Tsuboi, S., Solid State Commun. 48, 1071 (1983). The Raman TO linewidth for an a-Si80 C20 :H film is seen to be ∼80 cm−1, in good agreement with the linewidths observed in device quality a-Si:H (ref. 13). Presumably, from the present work, such a film (Xc = 20%) would have R* > 0.90.+0.90.>Google Scholar
16. As another example of local disturbances strongly affecting EO, see Aljishi, S., Smith, Z E., Slobodin, D., Kolodzey, J., Chu, V., Schwarz, R., and Wagner, S., Mater. Res. Soc. Symp 70, 269 (1986). There, large increases in Eo were observed with the onset of microcrystalline (local) inclusions in a-SiGe:H:F alloys.Google Scholar
17. Siebert, W., Jahn, K. and Fuhs, W., J. Non-Cryst. Solids 77–78, 869 (1985).Google Scholar
18. McMahon, T. J., private communication.Google Scholar
19. Xi, J. P., McMahon, T. J., Mahan, A. H. and Tsu, R., Solar Cells 21 (1987), in press.Google Scholar