Физика твердого тела, 2004, том 46, вып. 118 M.V. Stepikhova, M.F. Cerqueira, M. Losurdo, M.M. Giangregorio, E. Alves, T. Monteiro, M.J. Soares planes of silicon are visible in the figure. Statistical analysis  M.F. Cerqueira, M. Andritschky, L. Rebouta, J.A. Ferreira, M.F. da Silva. Vacuum 46, 1385 (1995).
of the nanocrystallites size distribution gives the nanocrystal  M. Losurdo, M.F. Cerqueira, E. Alves, M.V. Stepikhova, mean radius of about 1.5 nm for this sample. Note, the PL M.M. Giangregorio, G. Bruno. Physica E 16, 414 (2003).
response in the visible range at around 700–720 nm has  R. Swanepoel. J. Phys. E 16, 1214 (1998).
been also detected in these samples. We believe that in our  I.H. Campbell, P.M. Fauchet. Solid State Commun. 58, case the situation is similar to that observed by M. Fujii et (1986).
al. , who has studied the correlation between Er-related  M. Stepikhova, W. Jantsch, G. Kocher, L. Palmetshofer, PL intensity and the nc-Si grain sizes in nc-Si containing M. Schoisswohl, H.J. von Bardeleben. Appl. Phys. Lett. 71, SiO2 films doped with Er. These authors have obtained the 2975 (1997).
strong, by about two orders of magnitude, increase of Er  G.N. van Hoven, J.H. Shin, A. Polman, S. Lombardo, S.U. Campisano. J. Appl. Phys. 78, 2642 (1995).
PL intensity with the lowering of nc-Si grain sizes from 3. G. Franzo, V. Vinciguerra, F. Priolo. Appl. Phys. A 69, to 2.7 nm. Actually, starting with these sizes one can speak (1999).
about the remarkable bandgap widening and the role of  M. Losurdo, M.M. Giangregorio, P. Capezzuto, G. Bruno, quantum size effects in Si . Therefore one can conclude M.F. Cerqueira, M. Stepikhova, E. Alves. Appl. Phys. Lett.
that the seeming strange increase of PL intensity in our (2003), in print.
„amorphous samples“ can be also understood as a result  M. Fujii, M. Yoshida, S. Hayashi, K. Yamamoto. J. Appl. Phys.
of sensitizing effect of Si nanocrystals on Er ions that in 84, 4525 (1998).
related with the enhancement of the excitation probability  T. Takagahara, K. Takeda. Phys. Rev. B 46, 23, 15 578 (1992).
for the last ones due to the recombination of electron-hole pairs confines in nanocrystals.
4. Summary In this contribution we have shown the ability to produce by the reactive magnetron sputtering method effectively emitting nc-Si:H thin films doped with Er and have discussed their luminescent and structural properties.
The nc-Si:Er films with the well-defined crystallinity and nanocrystal sizes (varied from 1–3 to 8 nm) were deposited and studied in both near IR and visible luminescence ranges. The strong influence of Si nanocrystals on the films luminescent properties at 1.54 µm has been observed, where the most intense Er photoluminescence obtained relates to the low crystalline films with the nanocrystal grain sizes less than 3 nm. These films demonstrated intense 1.54 µm luminescence at room temperature with the temperature quenching coefficient (in the range 77–300 K) only of about 5. The results have been explained in terms of the sensitization effect of Si nanocrystals on Er rare-earth ions.
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Физика твердого тела, 2004, том 46, вып.