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Stability in Amorphous Silicon

Published online by Cambridge University Press:  26 February 2011

Z E. Smith  and
S. Wagner
Z E. Smith
Affiliation:
Department of Electrical Engineering, Princeton University, Princeton, NJ 08544
S. Wagner
Affiliation:
Department of Electrical Engineering, Princeton University, Princeton, NJ 08544
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Abstract

The experimental phenomena associated with light-induced degradation and thermal recovery of hydrogenated amorphous silicon (a-Si:H) films are reviewed, with special emphasis on the limitations of each experimental technique. When several techniques are used in concert, a fuller picture emerges. Recent experiments suggest different positions in the band-gap of the paramagnetic-associated defect states (the dangling bonds) for doped and undopedfilms; this information can be combined with conductivity, sub-bandgap optical absorption and electron spin resonance data to yield a model for the density of gap states (DOS) in a- Si:H, including how the DOS changes upon illumination and annealing.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 95: Symposium E – Amorphous Silicon Semiconductors--Pure and Hydrogenated , 1987 , 551
Copyright
Copyright © Materials Research Society 1987

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References

[1] Staebler, D.L. and Wronski, C.R., Appl. Phys. Lett. 31, 292 (1977)Google Scholar
[2] Hack, M. and Shur, M., Proc. 18th IEEE Photovolt. Spec. Conf., (IEEE, New York, 1985) p. 1588.Z E. Smith, and S. Wagner, Mat. Res. Soc. Symp. Proc. Vol. 49 (MRS, Pittsburgh, 1985) p. 331.Google Scholar
[3] Skumanich, A., Amer, N., Jackson, W. B, Phys. Rev. B 51, 3162 (1985).Google Scholar
[4] Slobodin, D., Aljishi, S., Schwarz, R., and Wagner, S., Mat. Res. Soc. Symp. Proc. Vol.49 (MRS, Pittsburgh, 1985) p. 153.Google Scholar
[5] Smith, Z. E., Chu, V., Shepard, K., Aljishi, S., Slobodin, D., Kolodzey, J., Wagner, S., and Chu, T.L., Appl. Phys. Lett. [in press].Google Scholar
[6] Street, R.A., Appl. Phys. Lett. 41, 1060 (1982).Google Scholar
[7] Street, R.A., Appl. Phys. Lett. 42, 507 (1983).Google Scholar
[8] We adopt the standard identification of the g=2.0055 resonance as a dangling Si bond. An alternate identification of this defect as an over-coordinated Si atom has been proposed IS. Pantelides, Phys. Rev. Lett. 57, 2979 (1986)]; this affects the arguements of the present paper only in nomenclature, except where noted.Google Scholar
[9] Jackson, W. B. and Amer, N.M., Phys. Rev. B. 25 5559 (1982).Google Scholar
[10] Stutzmann, M., Jackson, W.B., and Tsai, C.C., Phys. Rev. B 32, 23 (1985).Google Scholar
[11] Lee, C., Ohlsen, W.D., Taylor, P.C., Ullal, H.S., and Caesar, G.P., Phys. Rev. B 31, 100 (1985); C.Lee, W.D. Ohlsen, and P.C. Taylor, Mat. Res. Soc. Symp. Proc. Vol. 70, (MRS, Pittsburgh, 1986) p. 225.Google Scholar
[12] Guha, S., and Hack, M., J. Appl. Phys. 58, 1683 (1985); data discussed is that of data discussed is that of H. Dersch, L. Schweitzer and J. Stuke, Phys. Rev. B 46, 273 (1982), and R.A. Street, Philos. Mag. B. 46, 273 (1982).Google Scholar
[13] Staebler, D.L. and Wronski, C.R., J. Appl. Phys. 51, 3262 (1980).Google Scholar
[14] Rose, A., Concepts in Photoconductivity and Allied Problems (Krieger, Huntington NY, 1978).Google Scholar
[15] Johnson, N.M. and Jackson, W.B., J. Non-Cryst. Solids 77&78, 107 (1985).Google Scholar
[16] Notation: When the Fermi-level is below ED +/D o the dangling bonds are unoccupied (+), singly occupied (0) when ED +/D o <EF <ED o/D - , and doubly occupied (−) when EF >ED o/D - . These “levels” are actually the peaks of a distribution of levels, so when EF ED o/D - about half are (0) and half are (−).ED+o/D+-+.+These+“levels”+are+actually+the+peaks+of+a+distribution+of+levels,+so+when+EF+ED+o/D+-+about+half+are+(0)+and+half+are+(−).>Google Scholar
[17] Street, R.A., Phys. Rev. Lett. 49, 1187 (1982).Google Scholar
[18] Kocka, J., this volume.Google Scholar
[19] Stoddart, H., Vardeny, Z., and Tauc, J., Bull. Am. Phys. Soc. 32, 435 (1987).Google Scholar
[20] Conrad, K.A., and Schiff, E.A., Sol. State Comm. 60, 291 (1986).Google Scholar
[21] Madan, A., LeComber, P.G., Spear, W.E., J. Non-Cryst. Solids 20, 239 (1976).Google Scholar
[22] Fritzsche, H., J. Non-Cryst. Solids 77&78, 273 (1985).Google Scholar
[23] Parker, M.A., Conrad, K.A., and Schiff, E.A., Mat. Res. Soc. Syrup. Proc. Vol.70 (MRS, Pittsburgh, 1986) p. 125.Google Scholar
[24] Wronski, C.R. and Daniel, R.A., Phys. Rev. B 23,794 (1981).Google Scholar
[25] Wronski, C.R., Smith, Z. E., Aljishi, S., Chu, V., Shepard, K., Shen, D.-S., Sehwarz, R., Slobodin, D., and Wagner, S., AIP Conf. Proc. [in press].Google Scholar
[26] Shepard, K., Smith, Z E., Aljishi, S., and Wagner, S. [unpublished].Google Scholar
[27] Smith, Z. E. and Wagner, S., Phys. Rev. B 32, 5510 (1985).Google Scholar
[28] Guha, S., Huang, C.-Y., and Hudgens, S.J., Appl. Phys. Lett. 45, 50 (1984).Google Scholar
[29] Smith, Z. E., Aljishi, S., Slobodin, D., Chu, V., Wagner, S., Lenuhan, P.M., Arya, R.R., and Bennett, M.S., Phys. Rev. Lett. 57, 2450 (1986).Google Scholar
[30] McMahon, T.J. and Tsu, R., Appl. Phys. Lett. [in press].Google Scholar
[31] Redfield, D., AIP Conf. Proc. [in press].Google Scholar
[32] Delahoy, A. and Tonon, T., AIP Conf. Proc. [in press].Google Scholar
[33] Stutzmann et al. [10] noted that for moderate temperatures, the number of spins at long times was thermally activated with an activation energy of about 0.04 eV. They assumed that this could be incorporated into their model by writing csw(T)=csw(0)exp(Ecsw/kT) with Ecsw=0.04eV; as pointed out by Hack, M., Guha, S., and W. den Boer [Phys. Rev. B 33, 2512 (1986)], however, Ns∞csw 1/3, and so Ecsw should actually have been taken as 3×0.04=.12eV. Hack et al. offer a physical interpretation of the mechanism behind this. Because of the effect of simultaneous annealing, we find that the value of Ecsw which best fits the data is about 0.15eV.Google Scholar