Composite electrodes composed of silicon nanowires synthesized using the supercritical fluid-liquid-solid (SFLS) method mixed with amorphous carbon or carbon nanotubes were evaluated as Li-ion battery anodes. Carbon coating of the silicon nanowires using the pyrolysis of sugar was found to be crucial for making good electronic contact to the material. Using multiwalled carbon nanotubes as the c...

In this paper we present results on silicon thin films deposited by Hot-Wire CVD at low substrate temperature (200oC). Films ranging from amorphous to nanocrystalline were obtained by varying the filament temperature from 1500 to 1800oC. A crystalline fraction of 50% was obtained for the sample deposited at 1700oC. The results obtained seemed to indicate that atomic hydrogen plays a leading rol...

The 1.54 m photoluminescence and decay time of Er-doped amorphous silicon nitride films with different Si concentrations are studied in the temperature range of 4 to 320 K. The temperature quenching of the Er emission lifetime demonstrates the presence of nonradiative trap centers due to excess Si in the films. The temperature dependence and the dynamics of the energy coupling between amorphous...

Silicon heterojunction solar cells have high opencircuit voltages thanks to excellent passivation of the wafer surfaces by thin intrinsic amorphous silicon (aSi:H) layers deposited by plasma-enhanced chemical vapor deposition (PECVD). By using in-situ plasma diagnostics and ex-situ film characterization, we show that the best a-Si:H films for passivation are produced from deposition regimes clo...

Hydrogenated amorphous silicon alloys of carbon and germanium can be deposited by glow-discharge decomposition of gaseous hydrides or fluorides. Non-plasma methods such as photochemical vapour deposition are also used and offer guidelines for understanding and improving the standard glow-discharge method. These amorphous alloys usually have poorer structural and electronic properties than pure ...

In earlier work, we showed that exponential (Urbach) band-edge states were localized on connected subnetworks of short bonds for the valence tail and long bonds for the conduction tail for high-quality continuous random network models of amorphous silicon. Here, we study size effects by computing the electronic density of states for a 105-atom model of α-Si proposed by G. T. Barkema and N. Mous...

Crystalline semiconductors are very well known, including silicon (the basis of the integrated circuits used in modern electronics), Ge (the material of the first transistor), GaAs and the other III-V compounds (the basis for many light emitters), and CdS (often used as a light sensor). In crystals, the atoms are arranged in near-perfect, regular arrays or lattices. Of course, the lattice must ...

An engineered enhancement in short-circuit current density and energy conversion efficiency in amorphous silicon p-i-n solar cells is achieved via improved transmission of electromagnetic radiation arising from forward scattering by surface plasmon polariton modes in Au nanoparticles deposited above the amorphous silicon film. For a Au nanoparticle density of 3.7 108 cm−2, an 8.1% increase in s...

In this paper, we present the design and fabrication of hybrid dielectric-metallic back surface reflectors, for applications in thin film amorphous silicon solar cells. Standard multilayer distributed Bragg reflectors, require a large number of layers in order to achieve high reflectance characteristics. As it turns out, the addition of a metallic layer, to the base of such a multilayer mirror,...

In this work we study aluminium laser-fired contacts for intrinsic amorphous silicon layers deposited by Hot-Wire CVD. This structure could be used as an alternative low temperature back contact for rear passivated heterojunction solar cells. An infrared Nd:YAG laser (1064 nm) has been used to locally fire the aluminium through the thin amorphous silicon layers. Under optimized laser firing par...