Papers by Keyword: Antireflection

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Authors: Yi Lei, Wen Bin Wu
Abstract: Base on the hydraulic fracturing field test in soft coal seam, the rule which the cutting quantity is added and the drilling gas desorption index K1 is decreased, is analyzed from the perspective of physical-mechanical properties and adsorption-desorption law is changed, etc. And gas adsorption and desorption law was analyzed using the theory of two-phase flow, to determine the effect after fracturing coal extraction is improved and the main reason for reducing the outburst.
Authors: Wen Liang Wang, Xiao Hong Rong
Abstract: The refractive index of silicon material is very high, and antireflection coatings are widely used to improve conversion efficiencies of silicon solar cells. An ideal antireflection structure should lead to zero reflection loss on its surfaces over an extended solar spectral range for all angles of incidence. Based on optical thin film theory, a multilayer structure are adopted as initial stack, and with the aid of conjugate graduate optimized method, a broadband and wide-angle antireflection is designed for using on silicon solar cell. In our design, the incident angles of antireflection coating are considered from to , working wavelength ranges are considered from 400nm to 1200nm. Within these ranges, the design results show that it can reduce residual reflection evidently in theory.
Authors: Mabrouk Selmi, F. Chaabouni, Mohamed Abaab, Bahri Rezig
Abstract: RF magnetron sputtering is used to deposit Aluminum-doped zinc oxide (ZnO:Al) films on glass and p-Si substrates. This work is a study of ZnO:Al films grown at different RF powers for photovoltaic cells application, as antireflective (AR) coatings. At room temperature and argon gas pressure of 0.6 Pa, RF power was changed from 200 to 400 W. The structural, electrical and optical properties of ZnO:Al films were investigated. Under theses conditions, we have obtained c axis-oriented wurtzite structure ZnO thin films with high transmission (>85%) and low reflection in visible wavelength range and a band gap of 3.34 eV. The results of this study suggest that the variation of the RF power, used for growth, allows the control of the structural and optical properties of the films. ZnO:Al films can be used in optical applications as thin films antireflective coatings.
Authors: Wei Ying Ou, Wei Ming Lu, Lei Zhao, Wen Jing Wang, Zhong Quan Ma
Abstract: A novel method was proposed to form porous silicon (PS) antireflection layers and thin SiO2 films at the same time by HF/H2O2 treatment of acid-textured pn+ multicrystalline silicon. Porous silicon structures formed inside the cavities and the porosity became large with an increase of the treated time resulting in a dramatical decrease of reflectance. The reflectance decreased to less than 5% within the wavelength range of 420-970 nm after 5 min HF/H2O2 treatment. Furthermore, the minority-carrier lifetime showed an increase of about 42% for a short treated time because of the formation of a thin silicon oxide layer resulting the reduction of dangling silicon bonds in the interface between PS/Si.
Authors: Chun Mei Zhang, Tao Meng, Yan Ping Hao, Fu Ping Liu
Abstract: We show theoretically that the optical absorption of one-dimensional metallic photonic bandgap (MPBG) materials, which consist of alternating Ag and MgF2 layers, can be substantially enhanced by modifying the structure properly through decreasing the thickness of top MgF2 layer to half and increasing the thickness of bottom Ag layer to fivefold. Using transfer matrix method, absorption spectra and the electric field distribution profiles are numerically calculated. The absorption spectrum under reverse-direction incidence is also investigated. Based on strong and direction-dependent absorption properties, the proposed MPBG structure could allow many potential applications such as unique photothermal absorbing materials.
Authors: Chun Lin He, Xue Fei Yang, Guo Feng Ma, Jian Ming Wang, Zhao Fu Du, Dong Liang Zhao, Qing Kui Cai
Abstract: Antireflection of silicon surface is one key technology for manufacture of efficient solar cells. The noble metal assisted chemical etching Si wafer can quickly produce a black Si surface with a high porosity in HF-H2O2-H2O solution at room temperature. The pores formed are straight and vertical to the surface of Si. The porous Si surface exhibits a reflectivity of 2 % in the range of 200-1000 nm, which shows that this process is beneficial to improve the conversion efficiency and to decrease the cost of Si solar cells.
Authors: Yun Zhou, Su Shen, Jie Zhang, Peng Fei Jin, Yan Hua Liu
Abstract: Sub-wavelength antireflective structures are fabricated by using a soft roll-to-plate nanoimprinting lithography. The proposed methodology employs a modified polyurethane acrylate as a flexible mold due to its high resolution, chemical inertness, polymerization characteristics, and its non-wetting, very low surface energy. Large-format (750mm x 750mm) plastic film with the recombined double-sided sub-wavelength structures is obtained, which has fascinating broadband antireflective effect. The roll-to-plate ultra-voilet nanoimprinting provides the capability of patterning sub-100nm structures, a short period of process time and allows the fabrication of sub-wavelength structure on a large number of flexible or rigid substrates in an economic fashion.
Authors: Brij Mohan Kumar Prasad, Amrit Bawankan
Abstract: We report on a diode laser which is used to pump directly the crystal with a semiconductor saturable absorber allows passive mode locking for the generation of pulses with an average power along with the broadband light by focusing on ultrashort laser pulses into crystal tungstate. The nonuniformity can lead to the crystal and bonding failure. Also model the thermal and structural properties at the various tempeartures to observe the beam quality. Extends the generated spectrum from the infrared to ultraviolet through the visible region, it consists of discrete spatially separated sidebands.
Authors: Sung Hoon Hong, Eun Ju Hong, Byeong Ju Bae, Heon Lee
Abstract: Artificial polycarbonate moth eye structured plate was used to emboss the moth eye nano-pattern into PVC films. Embossing was done at 100°C to prevent any damage on polycarbonate template. With embossing of moth eye nano-patterns, transmittance of PVC film was increased up to 6% over 400nm to 800nm wavelength region. This embossed PVC film was then used as an imprint template after depositing thin layer of SiO2 and self-assembled monolayer. Consequently, polymer based moth eye nano-patterns were formed on glass template after UV imprinting and its transmittance was increased from 90% to 92%.
Authors: Cheng Chuan Wang, Chia Yun Chen, Ya Ching Chou
Abstract: Advances in nanofabrication have resulted in great potentials for improving in both device performance and the manufacturing process of various applications. One revolutionary example is silicon (Si) nanostructures, typically using Si nonopore arrays or Si nonowire arrays, to construct high efficient and low-cost solar cells. In this work, we develop the innovative combined nanostructure arrays with tailored structural profiles using inexpensive, simple and rapid etching processes, whose total reflection is suppressed to 1.6%, approximately 39% less than Si nonopore arrays, and 20% less than Si nanowire arrays. In addition, systematic investigations on wettability of textured Si surfaces reveal the inherent surface oxidation during etching process. These combined nanostructure arrays with tailored antireflection performances, along with the in-depth studies of underlying etching mechanisms, may benefit both the yield and cost efficiently in industrial standard of silicon solar cells.
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