We study the structural and electrical properties of intrinsic layer growth close to the transition between amorphous silicon (a-Si:H) and nanocrystalline silicon (nc-Si:H), deposited on glass and PEN without intentional heating. These samples showed different behaviour in Raman shift and XRD spectra when compared with that of samples deposited at 200 degrees C. Electrical properties of these films also reflect the transition between a-Si:H and nc-Si:H, and put in evidence some differences between the microstructure of the films grown on PEN and on glass. P- and n-doped layers were deposited onto glass substrate without intentional heating and at 100 degrees C with thicknesses ranging from 1000 nm to 35 nm. Conductivity measurements indicate the capability of doping this material, but, for very thin layers, substrate heating was found to be essential. (C) 2007 Elsevier B.V. All rights reserved.