In:
Journal of Applied Physics, AIP Publishing, Vol. 87, No. 4 ( 2000-02-15), p. 1882-1888
Kurzfassung:
Films were prepared by hot wire chemical vapor deposition at ∼240 °C with varied hydrogen dilution ratios R=H2:SiH4 from 1 to 20. The optical and electronic properties as a function of microcrystallinity were studied. We found: (a) At low H dilution R⩽2, there is no measurable crystallinity by Raman spectroscopy and x-ray diffraction in the a-Si:H matrix, but an optical absorption peak at ∼1.25 eV appears; when R=2, the film shows the lowest subgap absorption, the highest photosensitivity, and the largest optical gap. (b) When R⩾3, the c-Si phase is measurable by Raman and a low-energy photoluminescence (PL) band (0.84–1.0 eV) appears in addition to the high-energy band (1.3–1.4 eV). Meanwhile, all the absorption spectra show a featureless line shape. (c) An energy redshift is observed for both PL peaks as the film grows thicker. Finally, (d) the conductivity activation energy first decreases from 0.68 to 0.12 eV, then increases with increasing microcrystallinity. A mode of two sets of energy bands of electronic states for these two-phase materials is suggested.
Materialart:
Online-Ressource
ISSN:
0021-8979
,
1089-7550
Sprache:
Englisch
Verlag:
AIP Publishing
Publikationsdatum:
2000
ZDB Id:
220641-9
ZDB Id:
3112-4
ZDB Id:
1476463-5
