We deposited silicon thin films by plasma-enhanced chemical vapor depositio
n (PECVD) at very low substrate temperatures of 75 and 40 degreesC. Even at
these low deposition temperatures, the protocrystalline Si (pc-Si:H) exhib
its a high photosensitivity and remarkably enhanced stability against light
saturation. This material grows at the borderline between amorphous (a-Si:
H) and nanocrystalline (nc-Si:H) phases in the deposition parameter space.
Structural and optical characterization revealed a small fraction of crysta
llites embedded in an amorphous matrix. Thickness-dependent morphology of s
ilicon films was revealed by absolute constant photocurrent method (CPM). W
e demonstrated the effect of the amorphous-to-nanocrystalline transition on
the solar cell performance. The cells with a protocrystalline absorber lay
er showed an improved fill factor. (C) 2001 Elsevier Science B.V. All right
s reserved.