화학공학소재연구정보센터
Applied Surface Science, Vol.253, No.3, 1198-1204, 2006
Structural and photo-luminescence properties of nanocrystalline silicon films deposited at low temperature by plasma-enhanced chemical vapor deposition
Nanocrystalline silicon (nc-Si) films were prepared by a plasma-enhanced chemical vapor deposition method at a deposition temperature below 220 degrees C with different dynamic pressures (P-g), hydrogen flow rates ([H-2]), and RF powers, using SiH4/H-2/SiF4 mixtures. We examined the photoluminescence (PL) spectra and the structural properties. We observed two stronger and weaker PL spectra with a peak energies around E-PL = 1.8 and 2.2-2.3 eV, respectively, suggesting that the first band was related to nanostructure in the films, and another band was associated with SiO-related bonds. The nc-Si films with rather large PL intensity was obtained for high [H2] and/or low pressure values, However, effects of [H2] are likely to be different from those of P-g. The average grain size (delta) and the crystalline volume fraction (p) at first rapidly increase, and then slowly increase, with increasing P-g. Other parameters exhibited opposite behaviors from those of delta or p. These results were discussed in connection with the changes in the PL properties with varying the deposition conditions. (c) 2006 Elsevier B.V. All rights reserved.