Search results for "silicon"
showing 10 items of 1391 documents
<title>Multiphoton-absorption-induced structural changes in fused silica</title>
1991
The basic properties (light refractive index, density, mechanical strength, etc.) of fused silica are changed by the influence of high-intensity light from the glass transparency region capable of generating excitons by multiphoton absorption. The self-trapped exciton decay near the microcavity in the fused silica structure leads to the stable elementary intrinsic defect pair (nonbridging oxygen atom and three-fold-coordinated silicon atom) generation. At the large- enough light intensities near such a microcavity with a defect, the next exciton can be self- trapped. Then the next elementary defect can appear in the microcavity, and a chemical bond between it and the previously generated de…
Third-Generation Solar Cells: Concept, Materials and Performance - An Overview
2019
The large scarcity of natural fuels in earth crust has triggered to search alternative energy reservoirs for the future generation of human life. Because of large abundancy, solar energy is considered as big hope for the future generation energy utilization for commercial as well as home applications. The scientific revolution achieved in synthesis and processing of semiconductor nanomaterials, organic conducting polymers have led into new dimension in fabrication of future-generation solar cells. Reduction in the dimension of semiconductor nanomaterials significantly influences on their structural and optical properties which is helpful for the excellent photon harvesting. Also, their larg…
Biochemical Applications of Solid Supported Membranes on Gold Surfaces: Quartz Crystal Microbalance and Impedance Analysis
2003
Since their inception in 1985 by Tamm and McConnell [1], solid supported lipid bilayers have been widely used as model systems for cellular membranes [2]. They have been applied in fundamental and applied studies of lipid assemblies on surfaces, to study the structure of membranes and membrane dynamics, lipidreceptor-interactions and electrochemical properties of membranes [3-5]. Several attempts have been made to apply solid supported membranes (SSM) in biosensor devices [6]. Planar lipid membranes can be formed on various surfaces, i.e. glass, silicon, mica or metal surfaces such as platinum or gold. Surface attachment of the lipids is typically achieved following two different strategies…
<title>Proton conducting polymer electrolytes for electrochromic devices</title>
1997
This report concerns a composite proton electrolyte suitable for use in electrochromic devices. The electrolyte consists of nanosize hydrated oxide (aluminum, silicon or antimonic) particles suspended in a poly(vinyl acetate) matrix. All of the water was strongly bonded, thus making the electrolytes less harmful without considerably decreasing the conductivity. The proton conductivity of the electrolyte was approximately 10-4 S/cm at room temperature, practically independent of its amount of absorbed water.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Graphene p-Type Doping and Stability by Thermal Treatments in Molecular Oxygen Controlled Atmosphere
2015
Doping and stability of monolayer low defect content graphene transferred on a silicon dioxide substrate on silicon are investigated by micro-Raman spectroscopy and atomic force microscopy (AFM) during thermal treatments in oxygen and vacuum controlled atmosphere. The exposure to molecular oxygen induces graphene changes as evidenced by a blue-shift of the G and 2D Raman bands, together with the decrease of I2D/IG intensity ratio, which are consistent with a high p-type doping (∼1013 cm-2) of graphene. The successive thermal treatment in vacuum does not affect the induced doping showing this latter stability. By investigating the temperature range 140-350 °C and the process time evolution, …
Time-dependent simulation of Czochralski silicon crystal growth
1997
We have developed a detailed mathematical model and numerical simulation tools based on the streamline upwind/Petrov-Galerkin (SUPG) finite element formulation for the Czochralski silicon crystal growth. In this paper we consider the mathematical modeling and numerical simulation of the time-dependent melt flow and temperature field in a rotationally symmetric crystal growth environment. Heat inside the Czochralski furnace is transferred by conduction, convection and radiation, Radiating surfaces are assumed to be opaque, diffuse and gray. Hence the radiative heat exchange can be modeled with a non-local boundary condition on the radiating part of the surface. The position of the crystal-me…
Application of dynamic and combined magnetic fields in the 300mm silicon single-crystal growth
2002
Abstract The increase of diameter in the silicon single crystal growth from 200 to 300 mm for industrial application, and to 400 or 450 mm for research, respectively, has triggered off the development of numerous new technologies like crystal-growth-supporting systems, low-power hot zones, high strength of static magnetic fields and new quartzglas qualities. At Wacker Siltronic, new kinds of magnetic fields have been developed for 300 mm CZ growth. In this paper, the results of dynamic and combined (static and alternating) magnetic fields are discussed. Instead of buoyancy-driven convection, a magnetic-field-controlled melt flow has been obtained in large melt volumes. The crucible wall tem…
Analysis of the dopant segregation effects at the floating zone growth of large silicon crystals
1997
Abstract A computer simulation is carried out to study the dopant concentration fields in the molten zone and in the growing crystal for the floating zone (FZ) growth of large (> 100mm) Si crystals with the needle-eye technique and with feed/crystal rotation. The mathematical model developed in the previous work is used to calculate the shape of the molten zone and the velocity field in the melt. The influence of melt convection on the dopant concentration field is considered. The significance of the rotation scheme of the feed rod and crystal on the dopant distribution is investigated. The calculated dopant concentration directly at the growth interface is used to determine the normalized …
Convective phenomena in large melts including magnetic fields
2007
The set of characteristic parameters which describe modern large industrial CZ silicon single crystal growth systems is introduced. The main melt flow driving mechanisms are considered, and the characteristic density values of various in the melt acting forces are estimated. The analysis is illustrated with examples of numerical simulation and comparisons with experiments.
Enhancement of the Lifetime of Metastable States in Er-Doped Si Nanocrystals by External Colored Noise
2015
The changes in the lifetime of a metastable energy level in Er-doped Si nanocrystals in the presence of an external source of colored noise are analyzed for different values of noise intensity and correlation time. Exciton dynamics is simulated by a set of phenomenological rate equations which take into account all the possible phenomena inherent in the energy states of Si nanocrystals and Er^{3+} ions in the host material of Si oxide. Electronic deexcitation is studied by examining the decay of the initial population of the Er atoms in the first excitation level 4I_{13/2} through fluorescence and cooperative energy transfer upconversion. Our results show that the deexcitation process of th…