Function Of Silicon Concentration Research Articles

Thermal and electrical properties of siligraphene and its derivatives

The electrical and optical properties of siligraphene have been investigated in this paper using semi-classical Boltzmann equation and the WIEN2K code based on density functional theory. We studied two configurations of siligraphene (g-SiC3 and g-SiC7 with different concentration of Silicon); our results show that these two configurations are semiconductor materials with a direct band gap. We find that the electrical properties of siligraphene changes as a function of silicon concentration. We also compared optical properties of two structures of siligraphene and we found that the electrical properties increases as a function of silicon concentration and decreases as function of temperature.

Investigation of addition of silicon on the electrical properties of low temperature solution processed SiInZnO thin film transistor

Silicon indium zinc oxide (SIZO) TFTs are prepared by solution process at low temperature. The SIZO TFTs were investigated with respect to optical, electrical properties and structure. The effect of silicon contents into an IZO TFTs were investigated as a function of silicon concentration from 0.01 to 0.4 mol%. The silicon has more oxidized than In or Zn due to the low standard electrode potential. As Si concentration increased, the threshold voltage shifted toward positive direction and the off current decreased, systematically. Silicon indium zinc oxide (SIZO) TFTs are prepared by solution process. Carrier generation originated from the oxygen vacancy could be modified by adding Si since Si could be an oxygen vacancy suppressor. This is also related with the origin of defect state which was observed to be involved with the creation of oxygen vacancies. The OII/Otot ratio was decreased as increase silicon doping contents, indicating that the addition of Si atoms decreases the carrier concentration due to the lack of oxygen vacancy act as major carrier in oxide TFTs. The Si molar ratios in the solution can effectively control carrier concentration and saturation mobility.

Correlation between matrix structural order and compressive stress exerted on silicon nanocrystals embedded in silicon-rich silicon oxide

Silicon nanocrystals embedded in a silicon oxide matrix were deposited by radio frequency reactive magnetron sputtering. By means of Raman spectroscopy, we have found that a compressive stress is exerted on the silicon nanocrystal cores. The stress varies as a function of silicon concentration in the silicon-rich silicon oxide layers varies, which can be attributed to changes of nanocrystal environment. By conducting the Fourier transform infrared absorption experiments, we have correlated the stresses exerted on the nanocrystal core to the degree of matrix structural order.PACS78.67.Bf, 78.67.Pt, 73.63.Bd, 78.47.D, 74.25.Nd

Oxidation of silicon containing steel

Steels containing sufficient concentrations of silicon tend to form a low melting temperature oxide called fayalite, which then penetrates both the steel and any other oxide to form a mechanical key. As a consequence, routine descaling operations fail to remove all traces of FeO that remain attached to the final product and oxidise to form a red oxide blemish on the surface. The formation of oxides was investigated both experimentally and by developing a new theory that permits the simultaneous formation of a variety of oxides that compete to establish the final oxide structure. The theory forms the basis for studying the evolution of oxide scales as a function of silicon concentration.

Correlation between stress and carrier nonradiative recombination for silicon nanocrystalsin an oxide matrix

Silicon nanocrystals embedded in an oxide matrix formed in a multilayerarchitecture were deposited by the magnetron sputtering method. By means ofRaman spectroscopy we have found that compressive stress is exerted on thesilicon nanocrystal core. The stress varies as a function of silicon concentration (O/Si ratio) in the silicon-rich oxide (SRO) layers, which can be attributed to the changingnanocrystal environment. By conducting the time-resolved spectroscopy experiment, wedemonstrate that, depending on the nanocrystal surroundings, a different amount ofnonradiative recombination sites participates in the excited carrier relaxationprocess, leading to changes of the relative quantum yield of photoluminescence.

Calculation of the Electronic Structure and Energy Broadening of SixGe1?x Alloys

The Haydock recursion method is used to study the electronic structure of the Si x Ge 1-x alloy. The direct energy band gap of this material as a function of silicon concentration is calculated at the critical symmetry points Γ. X and L. A systematic theoretical study of the alloy's energy broadening, produced by disorder, at the same symmetry points is also presented. It was found that the broadening is significant mainly for the conduction band, while for the valence band it is negligible. The theoretical results are in satisfactory agreement with the reported experimental ones for the entire concentration range.

DX-center energy level dependence on silicon doping concentration in Al0.3Ga0.7As

The Hall free carrier concentration of silicon-doped Al0.3Ga0.7As alloys is studied as a function of both temperature and illumination. Different thermal activation energies were observed for the DX center as a function of silicon concentration. Excitation of the samples using an infra-red source also provided data for better insight into the DX center population. We correlated the incremental free electron photo persistent population with the activation energies obtained from the temperature dependence of the measured Hall concentration. We concluded that large free carrier concentrations can yield perturbations in the lattice potential that may alter the configuration coordinate energy barriers for capture and emission of electrons by and from the DX centers.

Evaluation of silicon doped CFCs for plasma facing material

To improve the CFCs characteristics of chemical erosion, tritium retention, and H 2O/air resistivity, silicon doped CFCs were developed in the framework of European Technology programme. The tritium retention, H 2O reaction kinetics, outgassing behaviour and depletion of silicon in doped CFCs were investigated as a function of silicon concentration and temperature. The results show that silicon in bulk of CFCs decreases the tritium bulk retention and the H 2O reactivity. However, it has been observed that the concentration of silicon is slightly decreased at elevated temperature. This paper presents the experimental results and the consequence is discussed.

Quasi-crystalline and amorphous phases as products of the rapid solidification of Al 80− xMn 20Si x alloys

The effect of rapid solidification is investigated in Al-Mn-Si alloys as a function of silicon concentration in order to clarify the conditions for the formation of quasi-crystalline (low silicon content) and amorphous (high silicon content) phases. Structural and thermal data for the equilibrium alloys have been collected and related to the transformation behaviour of the metastable phases. The transformation was followed by differential scanning calorimetry and diffraction techniques. The heats and temperatures of transformation measured in the present work are used in connection with the existing thermodynamic data for the Al-Mn system to rank the stability of the various phases.

Effects of Rocks and Backfill Materials on Waste Glass Leaching

AbstractExtensive studies have been made on the interactions between a waste glass and repository materials under static conditions. One of the PNC reference glasses was leached in the solution prepared from water in contact with crushed granite, tuff, diabase and backfill materials such as bentonite and zeolite. The leachant solutions except for some bentonite solutions reduced the glass leach rate compared with that measured in distilled water. The extent of the reduction was a function of silicon concentration in solution. The bentonite solutions enhanced the glass dissolution rate by a factor of 2 to 3 at low bentonite/water ratios but the effect was found to be less important at high bentonite/water ratios and in the long-term experiment. Addition of granite and zeolite to the bentonite solutions decreased the leach rate below the value measured in distilled water.

Solid Solubility of Amphoteric Silicon in Gallium Arsenide

The solid solubility isotherms for amphoteric silicon in GaAs are calculated as a function of silicon concentration along the gallium-arsenic-silicon liquidus isotherms. The regular solution approach is applied to a determination of the ternary liquidus surfaces. The temperature dependent equilibrium constants for the incorporation of silicon in GaAs are obtained by an extension of the previously reported method for evaluating the free energy changes involved in the transfer of silicon atoms from the arsenic to gallium sublattice. One of the interesting results is that the net carrier concentration in GaAs doped with amphoteric silicon alone can not exceed 1019 cm-3 under the single shallow acceptor model.

Electroluminescence Characteristics and Efficiency of GaAs:Si Diodes

The peak wavelength, spectral half-width, and efficiency of liquid-phase epitaxial GaAs:Si diodes were determined as a function of silicon concentration in the melt. The peak of the emission spectrum could be shifted from about 9200 to 10 000 Å by varying the silicon concentration. For all wavelengths investigated, uncoated diodes with 6% efficiency could be made, with some going as high as 10%. External room-temperature dc efficiencies up to 32% were measured on diodes provided with high-index glass domes. The spectral half-width was found to increase with silicon concentration, and was especially large for growth on the 111B plane. The internal absorption loss was found to be significant for all peak wavelengths. These findings are discussed in the light of current models of recombination processes in heavily doped semiconductors.