  We deposit intrinsic hydrogenated amorphous silicon (a-Si:H) thin films by
reactive pulsed laser deposition, for various hydrogen pressures in the 0-20 Pa
range, at a low deposition temperature of 120C, and investigate the hydrogen
incorporation, structural, optical, and electrical properties of the films, as
a function of the ambient hydrogen pressure. The film thickness decreases
linearly as the hydrogen pressure increases. The hydrogen content of the films
is determined by infrared spectroscopy and the optical bandgap from UV-Vis-NIR
transmittance and reflectance measurements. Electric measurements yield the
dark conductivity of the films. The hydrogen concentration of the films lies in
the 10^21-10^22 cm^(-3) range and increases with the hydrogen pressure until
the latter reaches 15 Pa, beyond which the hydrogen concentration decreases.
The optical bandgap and dark conductivity follow the hydrogen concentration
variation of the films. The dark conductivity lies in the 10^(-9)-10^(-10) S/cm
range. An unusually wide optical bandgap of 2.2-2.6 eV is observed.
