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Quasi-Fermi Energy and Steady-State Recombination Demarcation Level in a-Si:H

Published online by Cambridge University Press:  21 February 2011

J. Z. Liu
J. Z. Liu*
Affiliation:
NEC Research Institute, 4 Independence Way, Princeton, NJ 08540 U.S.A.
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Abstract

A specially designed photoconductivity experiment directly shows that, above room temperature, the steady-state recombination lifetime of the free electrons in undoped amorphous silicon can be described by the free electron quasi-Fermi energy alone. The apparent discrepancy on recombination demarcation levels between the Rose model and the Simmons-Taylor model is resolved by including the effect of the occupation function. The significance of the free electron quasi-Fermi level is discussed.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 258: Symposium A – Amorphous Silicon Technology – 1992 , 1992 , 759
Copyright
Copyright © Materials Research Society 1992

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References

REFERENCES

[1]. For general references, see Amorphous Silicon and Related Materials, ed. Fritzsche, H. (World Scientific, Singapore, 1989);CrossRefGoogle Scholar
Street, R. A., Hydrogenated Amorphous Silicon (Cambridge University Press, New York, 1991);Google Scholar
Overhof, H. and Thomas, P., Electronic Transport in Hydrogenated Amorphous Semiconductors (Springer-Verlag, New York, 1989).Google Scholar
[2]. Staebler, D.L. and Wronski, C.R., Appl. Phys. Lett., 31, 292 (1977).Google Scholar
[3]. Arene, E. and Baixeras, J., Phys. Rev. B 30, 2016 (1984).CrossRefGoogle Scholar
[4]. Hack, M., Guha, S., and Shur, M., Phys. Rev. B 30, 6991 (1984).Google Scholar
[5]. McMahon, T.J. and Xi, J.P., Phys. Rev. B 34, 2475 (1986).Google Scholar
[6]. Vaillant, F., Jousse, D., and Bruyere, J.-C., Phil. Mag. B 57, 649 (1988).CrossRefGoogle Scholar
[7]. Simmons, J.G. and Taylor, G.W., Phys. Rev. B 4, 502 (1971).Google Scholar
[8]. Taylor, G.W. and Simmons, J.G., J. Non-Cryst. Solids 8–10, 940 (1972).Google Scholar
[9]. Wronski, C.R. and Daniel, R.E., Phys. Rev. B 23, 794 (1981).Google Scholar
[10]. Rose, A., Concepts in Photoconductivity and Allied Problems (Robert E. Krieger Publishing, Huntington, New York, 1978), sections 3.7 in particular.Google Scholar
[11]. Liu, J.Z. and Wagner, S., Phys. Rev. B 39, 11156 (1989);CrossRefGoogle Scholar
Amorphous Silicon Technology-1989, Mater. Res. Soc. Proc. Vol. 149, edited by Madan, A., Taylor, P.C., LeComber, P.G., Thompson, M.J., and Hamakawa, Y. (MRS, Pittsburgh, 1989), p. 193.Google Scholar
[12]. Vomvas, A. and Fritzsche, H., J. Non-Cryst. Solids 97&98 (1987) 823. This work investigated the recombination lifetime vs. the temperature as the free electron quasi-Fermi level was fixed in phosphorous doped a-Si:H. Their data at low temperatures do not agree with Eq. (4) due to the non-negligible contribution of the tunneling between the gap states. Their data in the temperature region of the present work are inconclusive due to a calculation error (private communication with H. Fritzsche).CrossRefGoogle Scholar
[13]. Wronski, C. R., Lee, S., Hicks, M., and Kumar, S., Phys. Rev. Lett. 63, 1420 (1989).Google Scholar
[14]. The advantages of using undoped samples include the following: (1) EF- EF does not shift much with temperature and can be used as a reference energy; (2) EFn - EF is large enough under normal light intensity without introducing light-induced defects which will change the sample during the measurement.Google Scholar
[15]. The band to band recombination rate is much smaller than the recombination rate through the gap states, due to a high density of the gap states in a-Si:H. The hopping rate between the gap states is also much smaller than the rates considered here because the temperature is high. (Ref. 1)Google Scholar
[16]. Liu, J.Z., to be published.Google Scholar