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ISOTROPIC TEXTURING OF POLYCRYSTALLINE SILICON WAFERS
LWang,HShen,YFHu,
L.Wang
,H.Shen,YF.Hu

金属学报(英文版) , 2005,
Abstract: An isotropic etching technique of texturing silicon solar cells has been applied to polycrystalline silicon wafers with different acid concentrations. Optimal e tching conditions have been determined by etching rate calculation, scanning ele ctron microscope (SEM) image and reflectance measurement. The surface morphology of the textured wafers varies in accordance with the different etchant concentr ation which in turn leads to the dissimilarity of etching speed. Textured polycr ystalline silicon wafer surfaces display randomly located etched pits which can reduce the surface reflection and enhance the light absorption. The special rela tionship between reflectivity and etching rate was studied. Reflectance measurem ents show that isotropic texturing is one of the suitable techniques for texturi ng polycrystalline silicon wafers and benefits solar cells performances.
MAGNETIZATION BEHAVIOUR FOR TEXTURED BULK YBaCuO POLYCRYSTALLINE SUPERCONDUCTORS
TANG Hong,QIAO Guiwen,CHUANG YuchiInstitute of Metal Research,Chinese Academy of Sciences,Shenyang,ChinaXIANYU Ze,WANG JinxingNortheastern University,Shenyang,China,
TANG Hong
,QIAO Guiwen,CHUANG YuchiInstitute of Metal Research,Chinese Academy of Sciences,Shenyang,ChinaXIANYU Ze,WANG JinxingNortheastern University,Shenyang,China

金属学报(英文版) , 1994,
Abstract: In present paper, study of magnetization behaviour was carried out for textured bulk YBaCuO polycrystalline superconductors synthesized by MTG process. The magnetization behaviour apparently different from that of sintered samples was observed. Magnetization hysteresis measurements were performed for the textured YBaCuO superconductors at 77K in± 10kOe magnetic field range. Based on the results of magnetization hysteresis, the magnetic field dependence of critical current density (Jc) at 77K was evaluated for the textured YBaCuO samples. The magnetic flux penetration in textured bulk YBaCuO polycrystalline superconductors was investigated at 77K through the magnetization hysteresis measurements under various maximum applied magnetic fields (HM) and reasonable discussion for the phenomena was conducted in terms of Bean's critical state model. The enhancement of magnetic properties for textured hulk YBaCuO polycrystalline superconductors is presumably attributed to the improvement of microstructure in these samples.
TEM investigations of laser texturized polycrystalline silicon solar cell  [PDF]
J. Konieczny,L.A. Dobrzański,A. Dryga?a,J. Lel?tko
Archives of Materials Science and Engineering , 2012,
Abstract: Purpose: The presented in this paper research results concern investigation of phase transformation of the surface structure of polycrystalline silicon solar cell. The surface of boron doped polycrystalline silicon wafers were texturised by means of diode-pumped pulsed neodymium-doped yttrium aluminium garnet laser crystal (Nd:YAG). Investigations were carried out on transmission electron microscope (TEM) to observe the changes that occurred after laser treatment of the surface layer. Changes in microstructure of the surface layer of solar cells under the influence of the laser beam are presented using the analysis phase and dislocations present in the microstructure. Observations were carried out on prepared thin foils. Moreover, diffraction patterns from selected regions of textured wafers were solved to qualify phase transformations under influence of laser beam.Design/methodology/approach: Investigations were carried out on the Transmission Electron Microscope JEM 3010 supplied by JEOL with 300 kV accelerating voltage equipped with an electronic camera configured with a computer. The microstructure was obtained in the bright field image as well dark field working in a magnification range of 10000x to ca. 100000x. Phases identification was performed by means of selected area diffraction (SAD) method, where for diffraction pattern calculations the computer software “Eldyf” was used, kindly supplied by the Institute of Materials Science, University of Silesia.Findings: The research included analyze of the influence of laser treatment conditions on geometry, roughness and size of laser made surface texture of silicon wafer applied for solar cells.Research limitations/implications: Paper contributes to research on silicon surface processing using laser beam.Practical implications: Conducted investigations may be applied in optimisation process of solar cell surface processing.Originality/value: The range of possible applications increases for example as materials for solar cells placed on building constructions, elements in electronics and construction parts in automobile industry
Modelling of Light Trapping in Acidic-Textured Multicrystalline Silicon Wafers
Yang Li,Zhongtian Li,Yuebin Zhao,Alison Lennon
International Journal of Photoenergy , 2012, DOI: 10.1155/2012/369101
Abstract: Acidic texturing has been widely used to reduce the reflection losses for silicon solar cells fabricated on multicrystalline wafers, however, there are few available models which attempt to predict the reduced reflection after texturing based on the morphology of the textured surfaces. An optical model which simulates the light trapping and scattering effects of acidic-textured surfaces based on the surface morphology is presented. The developed model was experimentally verified by reflection measurements from multicrystalline silicon wafers textured using different etching conditions. The relationship between weighted average reflection and surface morphology is demonstrated with some of the trends being explained by simulating reflection in different wavelength regions. The developed model could be embedded into solar cell simulation tools or adapted to predict optical properties of diverse surface morphologies.
OBSERVATION ON DEFECTS IN POLYCRYSTALLINE SILICON THIN FILMS
YFHu,
Y.F.Hu
,H.Shen,L.Wang,Z.C.Liang,Z.Y.Liu,L.S.Wen

金属学报(英文版) , 2005,
Abstract: Polycrystalline silicon thin films were prepared by RTCVD (rapid thermal chemica l vapor deposition) method on several substrates such as SSP (silicon sheet from powder) ribbon, poly-Si wafer and mono-Si wafer. Intra-granular defects such as stacking faults, twins and microstructure defects were investigated on thin fil ms by scan electron microscopy (SEM) technique.
Ultralow-frequency spontaneous oscillations of the current in polycrystalline silicon  [PDF]
V. A. Dorosinets,N. A. Poklonski,V. A. Samuilov,V. F. Stel'makh
Physics , 2011,
Abstract: We report results of experimental study of ultralow-frequency spontaneous oscillations of the current in polycrystalline silicon films subjected to strong electric fields at room temperature.
TOPICAL REVIEW Textured silicon nitride: processing and anisotropic properties
Xinwen Zhu and Yoshio Sakka
Science and Technology of Advanced Materials , 2008,
Abstract: Textured silicon nitride (Si3N4) has been intensively studied over the past 15 years because of its use for achieving its superthermal and mechanical properties. In this review we present the fundamental aspects of the processing and anisotropic properties of textured Si3N4, with emphasis on the anisotropic and abnormal grain growth of β-Si3N4, texture structure and texture analysis, processing methods and anisotropic properties. On the basis of the texturing mechanisms, the processing methods described in this article have been classified into two types: hot-working (HW) and templated grain growth (TGG). The HW method includes the hot-pressing, hot-forging and sinter-forging techniques, and the TGG method includes the cold-pressing, extrusion, tape-casting and strong magnetic field alignment techniques for β-Si3N4 seed crystals. Each processing technique is thoroughly discussed in terms of theoretical models and experimental data, including the texturing mechanisms and the factors affecting texture development. Also, methods of synthesizing the rodlike β-Si3N4 single crystals are presented. Various anisotropic properties of textured Si3 N4 and their origins are thoroughly described and discussed, such as hardness, elastic modulus, bending strength, fracture toughness, fracture energy, creep behavior, tribological and wear behavior, erosion behavior, contact damage behavior and thermal conductivity. Models are analyzed to determine the thermal anisotropy by considering the intrinsic thermal anisotropy, degree of orientation and various microstructure factors. Textured porous Si3N4 with a unique microstructure composed of oriented elongated β-Si3N4 and anisotropic pores is also described for the first time, with emphasis on its unique mechanical and thermal-mechanical properties. Moreover, as an important related material, textured α-Sialon is also reviewed, because the presence of elongated α-Sialon grains allows the production of textured α-Sialon using the same methods as those used for textured β-Si3N4 and β-Sialon.
Activation Energy of Polycrystalline Silicon Thin Film Transistor  [PDF]
Alka Panwar,Mahesh Chandra,B.P. Tyagi
Journal of Nano- and Electronic Physics , 2011,
Abstract: The activation energy of a poly-Si thin film transistor is observed to be influenced by the grain size, trap state density and the inversion layer thickness. The present study aims to investigate these parameters theoretically so as to explore optimum conditions for the working of a polycrystalline silicon thin film transistor. Our computations have revealed that the activation energy decreases with the increase of gate bias for all values of grain size, trap states density and the inversion layer thickness. These findings are compared with the experimental results.
Quantification of Power Losses of the Interdigitated Metallization of Crystalline Silicon Thin-Film Solar Cells on Glass
Peter J. Gress,Sergey Varlamov
International Journal of Photoenergy , 2012, DOI: 10.1155/2012/814697
Abstract: The metallization grid pattern is one of the most important design elements for high-efficiency solar cells. This paper presents a model based on the unit cell approach to accurately quantify the power losses of a specialized interdigitated metallization scheme for polycrystalline silicon thin-film solar cells on glass superstrates. The sum of the power losses can be minimized to produce an optimized grid-pattern design for a cell with specific parameters. The model is simulated with the standard parameters of a polycrystalline silicon solar cell, and areas for efficiency improvements are identified, namely, a reduction in emitter finger widths and a shift toward series-interconnected, high-voltage modules with very small cell sizes. Using the model to optimize future grid-pattern designs, higher cell and module efficiencies of such devices can be achieved.
Polycrystalline Silicon ISFETs on Glass Substrate  [PDF]
Feng Yan,Pedro Estrela,Yang Mo,Piero Migliorato,Hiroshi Maeda
Sensors , 2005, DOI: 10.3390/s5040293
Abstract: The Ion Sensitive Field Effect Transistor (ISFET) operation based onpolycrystalline silicon thin film transistors is reported. These devices can be fabricated oninexpensive disposable substrates such as glass or plastics and are, therefore, promisingcandidates for low cost single-use intelligent multisensors. In this work we have developedan extended gate structure with PE-CVD Si3N4 deposited on top of a conductor, which alsoprovides the electrical connection to the remote TFT gate. Nearly ideal pH sensitivity(54 mV/pH) and stable operation have been achieved. Temperature effects have also beencharacterized. A penicillin sensor has been fabricated by functionalizing the sensing areawith penicillinase. The shift increases almost linearly upon the increase of penicillinconcentration until saturation is reached for ~ 7 mM. Poly-Si TFT structures with a goldsensing area have been also successfully applied to field-effect detection of DNA.
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