We present femtosecond studies of photoexcited carrier dynamics in hydrogenated amorphous silicon and silicon-germanium alloys grown by the hot-wire assisted chemical vapor deposition (HWCVD) technique, which is promising for producing high-quality device-grade materials. We have used wavelength-resolved femtosecond pump-probe techniques to study the dynamics of photoexcitations in these materi...

Nanostructures such as nanoparticles and nanowires have been demonstrated as powerful tools to improve light absorption[1-4], to enable low temperature process[5], to demonstrate multi-exciton generation[6], and to decouple the absorption depth and carrier diffusion length[7, 8]. Here we demonstrated the first amorphous silicon coreshell nanowire solar cells, which can be fabricated through a l...

Crystallization of amorphous silicon (a-Si) using excimer laser annealing (ELA) has been reported since 1994 by Watanabe group. It is known as the best method to fabricate a good poly-silicon because it can heat the film up to the melting point and, at the same time no thermal damage occur into the glass substrate (Carluccio et al., 1997; Matsumura and Oh, 1999). ELA technique is widely used to...

We report on the “mid-term” results obtained in the frame of the European FLEXCELLENCE project (www.unine.ch/flex). FLEXCELLENCE aims at developing the equipment and the processes for cost-effective roll-to-roll production of high-efficiency thin-film modules, based on amorphous (a-Si:H) and microcrystalline silicon (μc-Si:H). Eight partners, with extended experience in complementary fields ran...

Charge carrier dynamics in amorphous semiconductors has been a topic of intense research that has been propelled by modern applications in thin-film solar cells, transistors and optical sensors. Charge transport in these materials differs fundamentally from that in crystalline semiconductors owing to the lack of long-range order and high defect density. Despite the existence of well-established...

Amorphous silicon oxynitride (SiOxNy) thin films were grown by reactive high power impulse magnetron sputtering from a pure silicon target in Ar/N2O plasmas. The elemental composition of the films was shown to depend on the target surface conditions during the film deposition, as well as on the reactive gas flow rate. When the target was sputtered under poisoned surface conditions, the film com...

Nanocrystalline fluorinated silicon films are studied by using Raman spectroscopy, electron paramagnetic resonance, Fourier-transformed infrared spectroscopy, atomic force microscopy, nonlinear laser spectroscopy, and photoluminescence. Electrical properties of nanocrystalline silicon and amorphous silicon films were compared. The field-assisted migration of point defects is dramatic for durabi...

It is very interesting that magic electron affection promotes growth of nanocrystals due to nanoscale characteristics of electronic de Broglie wave which produces resonance to transfer energy to atoms. In our experiment, it was observed that silicon nanocrystals rapidly grow with irradiation of electron beam on amorphous silicon film prepared by pulsed laser deposition (PLD), and silicon nanocr...