Search results for "silicon"
showing 10 items of 1391 documents
Two years performance comparison of Elkem Solar multicrystalline silicon with polysilicon in a PV grid-connected system
2014
This abstract summarizes two years performance of an Elkem Solar and polysilicon photovoltaic (PV) system installed in the Sunbelt Region, which has been fully operational since 2011. The PV system consists of 28 multicrystalline silicon PV modules made from the standard Siemens process and from material produced by a metallurgical route - the Elkem Solar Silicon (ESS®) process. The present study suggests that after two years of field operation, both types of modules show similar degradation of power at STC. The ESS® PV modules have better performance than standard polysilicon modules as a function of solar irradiation, and thereby the total kWh generated has been slightly higher for the ES…
ELECTRON-PHONON COUPLING IN HEAVILY DOPED SILICON
2001
The coupling constant in electron-phonon interaction is a very important issue in nanoscale applications. We have measured this constant in heavily doped silicon. Electron-phonon interaction is proportional to T6 and the coupling constant is found to be 1.5 × 108 W/K5m³, which is about one tenth of the value in normal metals.
Electrical characterization of highefficiency bifacial silicon solar cells
2018
This work presents a preliminary study on the electrical characterization of high efficiency bifacial solar cells. An opening discussion on the state-of-the-art of such advanced technology is initially proposed and the experimental characterization of some prototypes is described. From this analysis, it can be stated that the bifacial silicon solar cells can be a very promising technology with high electrical performances and efficiency.
Photoconductivity and optical properties of silicon coated by thin TiO2 film in situ doped by Au nanoparticles
2013
Light trapping enhancement by plasmonic-active metal nanoparticles (NPs) is believed to be a promising approach to increase silicon-based solar cell efficiency. Therefore, we investigated TiO2 films in situ doped by Au NPs (TiO2:AuNPs) deposited by spin coating on a silicon substrate. Photoconductivity and optical properties of the TiO2:AuNPs/Si structures were studied in comparison with those of TiO2/Si reference samples. We found that an introduction of the 40–50 nm diameter AuNPs into the antireflective TiO2 layer deteriorates the antireflection properties and decreases the external yield of photogeneration of charge carriers. This is due to an increase of the layer reflection in the red…
Plasmonic layers based on Au-nanoparticle-doped TiO2 for optoelectronics: structural and optical properties.
2013
The anti-reflective effect of dielectric coatings used in silicon solar cells has traditionally been the subject of intensive studies and practical applications. In recent years the interest has permanently grown in plasmonic layers based on metal nanoparticles, which are shown to increase light trapping in the underlying silicon. In the present work we have combined these two concepts by means of in situ synthesis of Au nanoparticles in a dielectric matrix (TiO2), which is commonly used as an anti-reflective coating in silicon solar cells, and added the third element: a 10–20% porosity in the matrix. The porosity is formed by means of a controllable wet etching by low concentration HF. As …
Conductive Fused Porphyrin Tapes on Sensitive Substrates by a Chemical Vapor Deposition Approach.
2019
Abstract Oxidative polymerization of nickel(II) 5,15‐diphenyl porphyrin and nickel(II) 5,15‐bis(di‐3,5‐tert‐butylphenyl) porphyrin by oxidative chemical vapor deposition (oCVD) yields multiply fused porphyrin oligomers in thin film form. The oCVD technique enables one‐step formation, deposition, and p‐doping of conjugated poly(porphyrins) coatings without solvents or post‐treatments. The decisive reactions and side reactions during the oCVD process are shown by high‐resolution mass spectrometry. Owing to the highly conjugated structure of the fused tapes, the thin films exhibit an electrical conductivity of 3.6×10−2 S cm−1 and strong absorption in the visible to near‐infrared spectral regio…
Improving the material quality of silicon ingots by aluminum gettering during crystal growth
2016
We present a method for the purification of silicon ingots during the crystallization process that reduces significantly the width of the low charge carrier lifetime region at the ingot top. The back-diffusion of impurities from the ingot top is suppressed by adding a small amount of pure aluminum into the silicon melt right at the end of the solidification. We study the aluminum gettering effect by instrumental neutron activation analysis (INAA) and Fei imaging. Furthermore, we present a model for aluminum gettering of Fe in the silicon ingot that is in agreement with literature data for aluminum gettering at lower temperature. The distribution of iron in the ingots with and without alumin…
Increasing the stability of the Ge-containing extra-large pore ITQ-33 zeolite by post-synthetic acid treatments
2018
[EN] Extra-large pore ITQ-33 zeolite (ITT, 18 x 10 x 10-rings) is a very promising catalyst for the catalytic cracking of gasoil but, unfortunately, this material shows a limited hydrothermal stability due to the large germanium content present in the ITQ-33 structure. Taking this into account, the Ge-containing ITQ-33 has been post synthetically modified using different acid procedures with the aim of studying the effect of these treatments on the overall hydrothermal stability of this extra-large pore zeolite. In this sense, the as-prepared ITQ-33 has been treated with different HCl solutions in ethanol (from 0.1 to 1 M), containing also tetraethylorthosilicate (TEOS) as silicon precursor…
Study of silicon crystal surface formation based on molecular dynamics simulation results
2014
Abstract The equilibrium shape of 〈 110 〉 -oriented single crystal silicon nanowire, 8 nm in cross-section, was found from molecular dynamics simulations using LAMMPS molecular dynamics package. The calculated shape agrees well to the shape predicted from experimental observations of nanocavities in silicon crystals. By parametrization of the shape and scaling to a known value of { 111 } surface energy, Wulff form for solid-vapor interface was obtained. The Wulff form for solid–liquid interface was constructed using the same model of the shape as for the solid–vapor interface. The parameters describing solid–liquid interface shape were found using values of surface energies in low-index dir…
Efficiency comparison between SiC- and Si-based active neutral-point clamped converters
2015
This paper presents an efficiency comparison between silicon-carbide technology and silicon technology. In order to achieve this, the efficiency of an active neutral-point clamped converter built up with silicon carbide power-devices is compared with the efficiency of an active neutral-point clamped converter built up with silicon power-devices, under a particular operating mode and a particular selection of devices. Firstly, overall losses of both converters are estimated. Then, experimental tests are carried out to measure their overall losses and efficiency. Finally, experimental results are compared with the estimations to support the analysis. The efficiency of the SiC converter is hig…