Exponential band edges have been observed in a variety of materials, both crystalline and amorphous. In this Letter, we infer the structural origins of these tails in amorphous and defective crystalline Si by direct calculation with current ab initio methods. We find that exponential tails appear in relaxed models of diamond silicon with suitable extended defects that emerge from relaxing point...

We report on a novel optical thin film material, erbium-doped deuterated amorphous carbon, fabricated directly on silicon substrate at room-temperature via controlled thermal evaporation of a Metal-Organic compound in a Plasma-Enhanced Chemical Vapour Deposition (MO-PECVD) system. High erbium concentrations (up to 2.3 at.%) and room-temperature photoluminescence at 1.54 microm are successfully ...

In the present research, amorphous Fe73.5Si13.5B9Nb3Cu1 Finemet foils, 21-26µm in thickness and 5mm in width, were prepared by Planar Flow Casting (PFC) process. Wound cores of amorphous Finemet foils were simultaneously annealed and heat treated at 540°C for 60, 120 and 240 minutes in steam and air flow to form oxide insulating coating layer on both surfaces of the foils. The structure of nano...

Amorphous carbon (a-C) has been shown to be intrinsically p-type, and polymeric a-C ~PAC! possesses a wide Tauc band gap of 2.6 eV. We have replaced the p-type amorphous silicon carbide layer of a standard amorphous silicon solar cell with an intrinsic ultrathin layer of PAC. The thickness of the p layer had to be reduced from 9 to 2.5 nm in order to ensure sufficient conduction through the PAC...

We present a new analytical model to predict the spatial location of amorphous phases in ion-implanted singlecrystalline silicon using results of multidimensional Monte Carlo simulations. Our approach is based on the concept of the critical damage energy density [1]. Additionally, the self-annealing of radiation damage during ion implantation is taken into account because this effect is crucial...

We demonstrate a mechanism of solid-phase crystallization (SPC) enabled by nanoscale cavities formed at the interface between an hydrogenated amorphous silicon film and embedded 30 to 40 nm Si nanocrystals. The nanocavities, 10 to 25 nm across, have the unique property of an internal surface that is part amorphous and part crystalline, enabling capillarity-driven diffusion from the amorphous to...

For the first time, a method for sequential extraction of silicon (Si) from soils has been developed. This new method enables investigating different Si pools in soils and thus represents an important contribution to improve our understanding of biogeochemical Si-processes and global Si-cycling. The method fractionates and analyses various Si-pools, from the most mobile to immobile phases in so...

The ability to characterize the phase of the intrinsic (i) layers incorporated into amorphous silicon [a-Si:H] and microcrystalline silicon [μc-Si:H] thin film solar cells is critically important for cell optimization. In this research, a new method has been developed to extract the thickness evolution of the μc-Si:H volume fraction in mixed phase amorphous + microcrystalline silicon [(a+μc)-Si...

Here we report the demonstration of a GHz-speed Lithium Niobate (LiNbO3) modulator that uses an amorphous Silicon waveguide to strongly confine light. The compact (o1 mm) modulator is realized by low-temperature deposition of hydrogenated amorphous Silicon (a-Si:H) onto a x-cut LiNbO3 substrate. The a-Si:H provides tight waveguide mode confinement while allowing strong evanescent coupling to th...

Microresonators are ideal systems for probing nonlinear phenomena at low thresholds due to their small mode volumes and high quality (Q) factors. As such, they have found use both for fundamental studies of light-matter interactions as well as for applications in areas ranging from telecommunications to medicine. In particular, semiconductor-based resonators with large Kerr nonlinearities have ...