PREPARATION

Hydrogenated amorphous silicon thin films have been the subject of extensive research in the
past thirty years, boosted by applications and the challenging fimdamental issues related to this
disordered semiconductor (structure, doping, stability etc.) [1,2]. Here we focus on the growth
processes of a-Si:H, which determine, to a large extent, its optoelectronic properties and the
performance of related devices. The optimisation of a-Si:H deposition conditions implies a
complete understanding of the processes involved in its growth as well as the correlation
between the deposition conditions and the optical, structural and transport properties [2].
Because of the disordered nature of a-Si:H, the detailed characterisation of the film properties
and the correlation between the structure and the optoelectronic properties is still in progress
[I]. As a consequence, the optimisation of a-Si.H has been mostly achieved by trial and error,
and supported by fundamental studies which offer a better understanding of the growth
mechanisms and the necessary framework for a further improvement of this material.