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Photoelectron spectroscopic investigations of very thin a-Si:H layers

Published online by Cambridge University Press:  01 February 2011

M. Schmidt ,
A. Schoepke ,
O. Milch ,
Th. Lussky  and
W. Fuhs
M. Schmidt
Affiliation:
Hahn Meitner Institut Berlin, Abteilung Silizium-Photovoltaik, Kekuléstr. 5, D-12489Berlin, Germany
A. Schoepke
Affiliation:
Hahn Meitner Institut Berlin, Abteilung Silizium-Photovoltaik, Kekuléstr. 5, D-12489Berlin, Germany
O. Milch
Affiliation:
Hahn Meitner Institut Berlin, Abteilung Silizium-Photovoltaik, Kekuléstr. 5, D-12489Berlin, Germany
Th. Lussky
Affiliation:
Hahn Meitner Institut Berlin, Abteilung Silizium-Photovoltaik, Kekuléstr. 5, D-12489Berlin, Germany
W. Fuhs
Affiliation:
Hahn Meitner Institut Berlin, Abteilung Silizium-Photovoltaik, Kekuléstr. 5, D-12489Berlin, Germany
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Abstract

We report on a detailed study on gap-state distribution in thin amorphous silicon layers (a-Si:H) with film thicknesses between 5 nm and 20 nm on c-Si wafers performed by UV excited photoelectron spectroscopy (UV-PES). We measured how the work function, the gap state density, the position of the Fermi-level and the Urbach-energy depend on the layer thickness and the doping level of the ultra thin a-Si:H(n) layers. It was found, that for phosphorous doping the position of the Fermi level saturates at EF–EV=1.47 eV. This is achieved at a gas phase concentration of 10000 ppm PH3 in the SiH4/H2 mixture which was used for the PECVD deposition process. The variation of the doping level from 0 to 20000 ppm PH3 addition results in an increase of the Urbach energy from 65 meV to 101 meV and in an increase of the gap state density at midgap (EV-Ei= 0.86eV) from 3·1018 to 2·1019 cm-3eV-1.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 762: Symposium A – Amorphous and Nanocrystalline Silicon-Based Films – 2003 , 2003 , A19.11
Copyright
Copyright © Materials Research Society 2003

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References

[1] Roedern, B. von, Ley, L., Cardona, M., Smith, F.W., Phil. Mag. B, 40, 433 (1979).Google Scholar
[2] Wiener, K., Ley, L., Phys. Rev. B, 36, 6072 (1987).Google Scholar
[3] Prutton, M., Introduction to Surface Physics p.24, Clarendon press, Oxford 1994, p. 23.Google Scholar
[4] Tanaka, M., Taguchi, M., Matsuyama, T., Sawada, T., Tsuda, S., Nakano, S., Hanafusa, H., Kuwano, Y., Jpn. J. Appl. Phys. 31, 3518 (1992).Google Scholar
[5] Scherff, M.L., Froitzheim, A., Uljaschin, A., Schmidt, M., Fahrner, W.R., Fuhs, W., Proceedings European Photovoltaic Conference, Rome (2002) (in press).Google Scholar
[6] Street, R.A., Hydrogenated amorphous silicon, Cambridge university press, Cambridge 1991; Emis data review series No.19, Amorphous silicon and its alloys, ed. by T. Searl, INSPEC, London 1998.Google Scholar
[7] Spicer, W. E., Phys. Rev. 112, 114 (1958).Google Scholar
[8] Jackson, W.B., Kelso, S. M., Tsai, C.C., Allen, J.W., Oh, S.-J., Phys. Rev. B, 31, 5187 (1985).Google Scholar
[9] Jackson, W.B., Oh, S.-J., Tsai, C.C., Allen, J.W., Phys. Rev. Lett. 53, 1481 (1984).Google Scholar
[10] Sebastiani, M., Gaspare, L.Di, Capellini, G., Bittencourt, C., Evangelisti, F., Phys. Rev. Lett. 75, 3352 (1995).Google Scholar