|Michigan Tech's Open Sustainability Technology Lab.|
Abstract:Reasons for choosing Etching process
Reference:Award-Winning Etching Process Cuts Solar Cell Costs (Revised) (Fact Sheet), The Spectrum of Clean Energy Innovation, NREL (National Renewable Energy Laboratory) - 50063.pdf
Abstract:Comparision among Silicon oxide,titanium oxide and Pure Sillicon as ARC in Etching Process
Conclusion:Sillicon oxide is the best ARC,which enhanced 20.6% in short circuit current,decreasing reflection,thus improving efficiency.
Reference:Etching, Evaporated Contacts and Antireflection Coating on Multicrystalline Silicon Solar Cell Author:A. Ibrahim, A.A. El Amin
---etching by means of reactive ion etching with SF6, or CHF3,/SF6,. ---Two type of ARC used:
(A)Graphaite Covered with conducting Sic,the graphite acts as base contact of the cells. (B) Graphite encapsulated with insulating Sic- and Si02/SiN/Si02-layers (ONO) leads to solar cells on insulating foreign substrates in Method B,the efficiency was improved by 11%:
future scope:same experiment using wet processing
Reference:Ludemann, R., Schaefer, S., Schule, C. and Hebling, C., 1997, January. Dry processing of mc-silicon thin-film solar cells on foreign substrates leading to 11% efficiency. In Photovoltaic Specialists Conference, 1997., Conference Record of the Twenty-Sixth IEEE (pp. 159-162). IEEE.
Description:For normally incident light falling upon periodic textures, angles of 45° ensure double-bounce reflectances will occur; angles of 60° yield triple-bounce reflectances at least. As facet tilt angles decrease below a , 45°, less and less light will receive double-bounce incidence, closer to the base of the grooves, until at angles below 30°, no light will receive multiple bounce incidence in air, and reflectance levels are equivalent to that of polished silicon
references: Alkaline Etching for Reflectance Reduction in Multicrystalline Silicon Solar Cells J. D. Hylton,z A. R. Burgers, and W. C. Sinke
Reference:Effect of Ag Particle Size in Thick-Film Ag Paste on the Electrical and Physical Properties of Screen Printed Contacts and Silicon Solar Cells Mohamed M. Hilali,a Kenta Nakayashiki,a Chandra Khadilkar,b Robert C. Reedy,c Ajeet Rohatgi,a Aziz Shaikh,d Steve Kim,d and Srinivasan Sridharanb
Result:Small to medium Ag particles reduce the series resistance,higher shunt resistance,decrease the leakage current and improve the fill factor Thus improving the efficiency by 17.4%
Reference:Anti-reflective coatings: A critical, in-depth review Hemant Kumar Raut,Anand Ganesh,Sreekumaran Nairb and Seeram Ramakrishna
description:abour ARC in daily life,advantage of ARC in Solar cell
you can read it for your knowledge..
Reference:ZnO Nanostructures as Efficient Antireflection Layers in Solar Cells Yun-Ju Lee,* Douglas S. Ruby, David W. Peters, Bonnie B. McKenzie, and Julia W. P. Hsu
description: between SiN and ZnO,Zno acts as better ARC
future scope:we may further improve ARC performance by tailoring the thickness of the bottom fused ZnO layer and through better control of tip tapering.
Reference:Pyramidal texturing of silicon solar cell with TMAH chemical anisotropic etching by P. Papet, O. Nichiporuk, Kaminski, Y. Rozier, J. Kraiem,J.-F. Lelievre, A. Chaumartin, A. Fave, M. Lemiti
finding:here TAMH is compared among NaOH and KOH. by using TMAH pyramidal texture and SiNx:H ARC, 2.7% less reflectance is obtained
Result:TMAH pyramidal texture and SiNx:H ARC is substituted traditional Alkaline solution.so now it is used in front surface to reduce reflectance and to improve light trapping.
Reference:Texture etched ZnO:Al coated glass substrates for silicon based thin Ælm solar cells O. Kluth, B. Rech, L. Houben, S. Wieder, G. Scho,C. Beneking,H. Wagner,A.Lo,H.W. Schock
description:here,the substrate is etched with HCL solution and in the DC and RF sputtering on glass substrates from ceramic (ZnO:(Al)2(O)3 and metallic (Zn:Al) targets respectively,then it is compared with electro-opto properties of smooth ZnO substrate.
result:by this,separate optimization of the electro-optical and light scattering properties was done.resistivity decreased,reflection loss decreased,and transmitting capacity increased
future scope:he light scattering properties of suitable Films can be controlled over a wide range simply by varying the etching time. Moreover, the electrical properties are not affected by the etching process. Thus, within certain limits a separate optimiza-tion of the electro-optical and light scattering properties is possible.
Reference:Enhanced Conversion Efficiencies of Cu2ZnSnS4-Based Thin Film Solar Cells by Using Preferential Etching Technique Hironori Katagiri, Kazuo Jimbo, Satoru Yamada, Tsuyoshi Kamimura, Win Shwe Maw, Tatsuo Fukano1� , Tadashi Ito1, and Tomoyoshi Motohiro1
description:Cu2ZnSnS4 (CZTS) is deposited in Rf sputtering in Mo coated Sodium Lime glass and then etched by deionized water for 10min and then a buffer layer of Cds is deposited ...then the sampled is checked for electro optical parameters and found that deionised water etched sample has 18% better conversion efficiency.
Reference:Photovoltaic performance of c-Si wafer reclaimed from end-of-life solar cell using various mixing ratios of HF and HNO3 Jun-Kyu Leea,c, Jin-Seok Leea,⁎, Young-Soo Ahna, Gi-Hwan Kangb, Hee-Eun Songb,Jeong-In Leeb, Min-Gu Kangb, Churl-Hee Choc,
Description:by mixing in ratio 83:17 of HF and HNO3 the the conversion efficiency of solar cell increased by 18.9% which is 17.6% of original
Reference:Improved stability of CdTe solar cells by absorber surface etching Ivan Rimmaudoa,1, Andrei Salaveia,2, Elisa Artegiania, Daniele Menossia, Marco Giarolab,Gino Mariottob, Andrea Gasparottoc,Alessandro Romeoa,description:different reasons for degradation of CdTe solar cell investigated and new methods are proposed
finding:it is found that in presence of Cu,its diffusion into CdTe Surface decreases the solar cell performance.So 40s Br-MeOh etching and 2 nm of Cu deposited on top of it.Now the diffusion rate decreased drastically and thus cell performance improved.and now the new sample is more stabe than the previous one..
Description:Alkali solutions are not suitable to etch due to anisotropic etching.So here a a two step etching process is developed to obtain a flast surface.so now a sodium hydroxide solution,followed by a sodium hydroxide-sodium hypochlorite solution etching is done.
finding:here we removed the isotropically damaged layer by this etching process and improvement in short circuit current and open circuit voltage thus efficiency is improved..
Reference:Pre-texturing multi-crystalline silicon wafer via a two-step alkali etching method to achieve efficient nanostructured solar cells Fenqin Hua, b, Yun Suna, b, Jiawei Zhaa, b, Kexun Chena, b, Shuai Zoua, b, Liang Fanga, b, , , Xiaodong Su
Refernce:Garcia-Llamas, E., Merino, J.M., Gunder, R., Neldner, K., Greiner, D., Steigert, A., Giraldo, S., Izquierdo-Roca, V., Saucedo, E., León, M. and Schorr, S., 2017. Cu 2 ZnSnS 4 thin film solar cells grown by fast thermal evaporation and thermal treatment. Solar Energy, 141, pp.236-241.
description:CZTS solar cells fabricated by a rapid thermal evaporation of Curich kesterite powder followed by annealing under Ar atmosphere.with slower heating better diffusion of elements observed.here first the absorbed layer is etched with (NH 4) 2 S and and before depositng the buffer layer the sample is etched with KCN.it removed the possible oxides deposited on the sample,and finnally improving the efficeincy.
Reference:Tao, Y., Madani, K., Cho, E., Rounsaville, B., Upadhyaya, V. and Rohatgi, A., 2017. High-efficiency selective boron emitter formed by wet chemical etch-back for n-type screen-printed Si solar cells. Applied Physics Letters, 110(2), p.021101.
description:Selective boron emiiter formed by wet chemical etch back by using a solution of HF/HNO3/H2O volume ratio (3:2:15).so to increase the rate of reaction NaNO2 is used which produces Porous sillicon. To make the surface less pyramidal it is again etched with KOH solution and after a high temperature oxidation above 1000 C and subsequent SiO2 removal in diluted HF (5%) solution, the pyramid surface becomes smooth.This results a higher open circuit volatage which improves the efficiency of front junction to 21.04%
reference:Jovanov, V., Moulin, E., Haug, F.J., Tamang, A., Bali, S.I., Ballif, C. and Knipp, D., 2017. From randomly self-textured substrates to highly efficient thin film solar cells: Influence of geometric interface engineering on light trapping, plasmonic losses and charge extraction. Solar Energy Materials and Solar Cells, 160, pp.141-148.
description:geometrical interface engineering is a powerful tool to improve the efficiency of solar cell.This is done by deposition and post deposition of Ar plasma treatment,by this method electro-opto properties of solar cell can be improved.
reference:Olusola, O.I., Madugu, M.L., Ojo, A.A. and Dharmadasa, I.M., 2017. Investigating the effect of GaCl 3 incorporation into the usual CdCl 2 treatment on CdTe-based solar cell device structures. Current Applied Physics, 17(2), pp.279-289.
description: at first cdcl 2 treated with CdTe based solar cell,after that efficiency got improved by 2% then when GaCl3 is mixed with CdCl 2 the overall got improved by 6%.so this is very helpful in improving the efficiency
reference:Yao, L., Ao, J., Jeng, M.J., Bi, J., Gao, S., Sun, G., He, Q., Zhou, Z., Sun, Y. and Chang, L.B., 2017. A CZTSe solar cell with 8.2% power conversion efficiency fabricated using electrodeposited Cu/Sn/Zn precursor and a three-step selenization process at low Se pressure. Solar Energy Materials and Solar Cells, 159, pp.318-324.
description: Three-step selenization at low Se pressure i.e 4.6pa and annealing 500 Celsius,570 Celsius and 500 Celsius respectively is performed on an electro-deposited Cu/Sn/Zn precursor,no etching is required,this improves the short circuit current, open circuit voltage and fill factor are improved so efficiency of solar cell is increased by ignoring the effect of MoSe 2
reference:Zheng, C., Shen, H., Pu, T., Jiang, Y., Tang, Q., Yang, W., Chen, C., Rui, C. and Li, Y., 2017. High-Efficient Solar Cells by the Ag/Cu-Assisted Chemical Etching Process on Diamond-Wire-Sawn Multicrystalline Silicon. IEEE Journal of Photovoltaics, 7(1), pp.153-156.
description:diamond-wire-sawn (DWS) multicrystalline silicon (mc-Si)wafer texturation based on the metal-assisted chemical etchin process with Ag/Cu dual elements to form uniform antireflection structures and nanostructure rebuilding(NSR) treatment to remove the saw marks and to realize uniform invert pyramid textured structures
result:here efficiency of Bmc-Si,mc-si,Ipmc-si is compared and efficiency of Ipmc-si is found to be maximum..
reference:Rahman, T., Bonilla, R.S., Nawabjan, A., Wilshaw, P.R. and Boden, S.A., 2017. Passivation of all-angle black surfaces for silicon solar cells. Solar Energy Materials and Solar Cells, 160, pp.444-453.
Result:Ultra-low reflectivity ( < 2%) was achieved by texturing a silicon surface with a hybrid structure of pyramids decorated with dense,vertically-aligned nanowire arrays, using cheap, scalable wet-etching processes.To passivate the textured surfaces, a conformal coating of alumina was formed on it by increasing the precursor diffusion time in the ALD process
Reference:Angeles-Ordóñez, G., Regalado-Pérez, E., Reyes-Banda, M.G., Mathews, N.R. and Mathew, X., 2017. CdTe/CdS solar cell junction activation: Study using MgCl 2 as an environment friendly substitute to traditional CdCl 2. Solar Energy Materials and Solar Cells, 160, pp.454-462.
description:in this,MgCl 2 is used instead of traditional CdCl 2 for solar cell activation and found that , the device parameters such as Voc, Jsc, FF, and efficiency were comparable or slightly higher for devices activated with MgCl2. dispersion efficiency became smaller and better spatial uniformity is obtained.
reference:Shin, J., Park, J. and Park, N., 2017. A method to recycle silicon wafer from end-of-life photo voltaic module and solar panels by using recycled silicon wafers. Solar Energy Materials and Solar Cells, 162, pp.1-6.
results:in this paper,method to recycle sillicon wafer from end of life PV module is explained.at first Ag and Al metal electrodes were dissolved sequentially in solutions of HNO3 and KOH,then Impurities on the wafer surface were removed by using an etching paste containing H3PO4 which is environment friendly.The thickness of the recycled wafers was > 180 µm, which is sufficient for current manufacturing processes for solar cells.Solar cells fabricated with the recycled wafers showed an efficiency equivalent to that of virgin cells
reference:Spinelli, P., Verschuuren, M.A. and Polman, A., 2012. Broadband omnidirectional antireflection coating based on subwavelength surface Mie resonators. Nature communications, 3, p.692.
description:an array of low aspect-ratio Si nanocylinders etched into a Si wafer shows an average reflectivity as low as 1.3% in the 450–900 nm spectral range.The strongly reduced reflectivity is observed for angles of incidence up to 60°.
reference:Kim, Y.B. and Kim, C.H., Samsung Electronics Co., Ltd., 2001. Method of forming a photoresist pattern on a semiconductor substrate using an anti-reflective coating deposited using only a hydrocarbon based gas. U.S. Patent 6,214,637.
description:at a highly reflective layer is formed and then by using hydrocarbon gas ARC is formed.then the ARC and the highly reflective layer under the photoresist pattern are etched using the photoresist pattern as a mask.then they are simultenously removed.
reference:Lucas, K., Adetutu, O., Hobbs, C.C., Musgrove, Y. and Lii, Y.J.T., Motorola Inc., 1999. Tantalum oxide anti-reflective coating (ARC) integrated with a metallic transistor gate electrode and method of formation. U.S. Patent 6,004,850.
description:at first,MOS metallic gate electrode layer over a substrate is deposited,then the ARC layer preferably tantalum pentoxide or a tantalum pentoxide layer doped with one or more of nitrogen atoms and/or silicon atoms is formed on that layer.Then it is exposed to UV light to improve the opto electrical property and finally etched with fluorine-chlorine-fluorine time-progressed reactive ion etch (RIE) process
reference:Schirone, L., Sotgiu, G. and Califano, F.P., 1997. Chemically etched porous silicon as an anti-reflection coating for high efficiency solar cells. Thin Solid Films, 297(1), pp.296-298.
description:porous sillicon was formed in mono and multi crystaline si Substrate by strain etching.by this we were able to reduce 3% reflectance and opto electrical property was improved hence efficiency upto 12% obtained
reference:Lalanne, P. and Morris, G.M., 1997. Antireflection behavior of silicon subwavelength periodic structures for visible light. Nanotechnology, 8(2), p.53.
description:in this method,a photo resist mask and top of which reactive ion etching is done to transfer primary mask to sillicon substrate.by this perormance improved
reference:Garnett, E. and Yang, P., 2010. Light trapping in silicon nanowire solar cells. Nano letters, 10(3), pp.1082-1087.
description:a better method to improve efficiency of solar cell (not very helpful)
reference:Zhao, J. and Green, M.A., 1991. Optimized antireflection coatings for high-efficiency silicon solar cells. IEEE Transactions on Electron Devices, 38(8), pp.1925-1934.
description:methods to improve efficiency of ARCs by a thin passivating silicon dioxide layer under the coating
reference:Striemer, C.C. and Fauchet, P.M., 2002. Dynamic etching of silicon for broadband antireflection applications. Applied physics letters, 81(16), pp.2980-2982.
description:electro chemical etching process is developed to measure the contineous porosity of porous sillicon layer in the form of etching depth and by this film reflectivity is reduced
reference:Bilyalov, R.R., Stalmans, L., Schirone, L. and Levy-Clement, C., 1999. Use of porous silicon antireflection coating in multicrystalline silicon solar cell processing. IEEE Transactions on electron devices, 46(10), pp.2035-2040.
description:different method to improve efficiency
reference:Li, Y., Zhang, J. and Yang, B., 2010. Antireflective surfaces based on biomimetic nanopillared arrays. Nano Today, 5(2), pp.117-127.
description:instead of anti reflective coating ,ARsurface is created here using Fresnel reflection..then using etching etching process,irregularities removed
reference:Nositschka, W.A., Beneking, C., Voigt, O. and Kurz, H., 2003. Texturisation of multicrystalline silicon wafers for solar cells by reactive ion etching through colloidal masks. Solar Energy Materials and Solar Cells, 76(2), pp.155-166.
description:here texturiasation of multicrystalline sillicon by RIE followed by natural lithography is done by which reflectance is decreased
reference:Ionov, P., Kim, S.H. and Li, D., Applied Materials, Inc., 2000. Method for etching silicon oxynitride and inorganic antireflection coatings. U.S. Patent 6,013,582.
description:this patent suggest that before before going for plasma etching,patterning stack of at least one layer comprising either a dielectric-comprising antireflective material or an oxygen-comprising material is required.
reference:Ionov, P., Kim, S.H. and Li, D., Applied Materials, Inc., 2000. Method for etching silicon oxynitride and inorganic antireflection coatings. U.S. Patent 6,013,582.
description:PECVD SiNx layers deposited on Multi-Si .there by Low surface recombination velocity and significant improvements in bulk quality is obtained
reference:King, D.L. and Buck, M.E., 1991, October. Experimental optimization of an anisotropic etching process for random texturization of silicon solar cells. In Photovoltaic Specialists Conference, 1991., Conference Record of the Twenty Second IEEE (pp. 303-308). IEEE.
description:aqueous potassium-hydroxide (KOH) solutions with isopropyl alcohol (IPA) added as a complexing agent.with varing solution time,solution temp,degeree of mechanical mixing and concentration of respective solution,12% less reflectance is obtained
reference:Zhou, W., Tao, M., Chen, L. and Yang, H., 2007. Microstructured surface design for omnidirectional antireflection coatings on solar cells. Journal of Applied Physics, 102(10), p.103105.
description:by using partially spherical structure,reflection closed rto zero is obtained
reference:Zhao, J., Wang, A., Green, M.A. and Ferrazza, F., 1998. 19.8% efficient “honeycomb” textured multicrystalline and 24.4% monocrystalline silicon solar cells. Applied Physics Letters, 73(14), pp.1991-1993.
description:thermally grown oxide folled by isotropic etching leads to hexagonally symmertric honeycomb structure in multi crystaline sillicon wafer which leads to more efficiency
reference:Singh, P.K., Kumar, R., Lal, M., Singh, S.N. and Das, B.K., 2001. Effectiveness of anisotropic etching of silicon in aqueous alkaline solutions. Solar Energy Materials and Solar Cells, 70(1), pp.103-113.
description:another oxide layer with gold on n type GaAs layer leads to improve the efiifciency
reference:Krotkus, A., Grigoras, K., Pačebutas, V., Barsony, I., Vazsonyi, E., Fried, M., Szlufcik, J., Nijs, J. and Levy-Clement, C., 1997. Efficiency improvement by porous silicon coating of multicrystalline solar cells. Solar Energy Materials and Solar Cells, 45(3), pp.267-273.
descripition:Porous silicon (PS) layer formation by an electrochemical etching in hydrofluoric acid based electrolyte which lead to 30% improved efficiency
reference:Nagayama, T., Sony Corporation, 1998. Semiconductor device in which an anti-reflective layer is formed by varying the composition thereof. U.S. Patent 5,831,321.
description:anti reflective layer is formed by dry etching of SiOx, SiNx and Six Oy Nz.
Reference:Enhanced Efficiency of Light-Trapping Nanoantenna Arrays for Thin Film Solar Cells
Constantin R. Simovski, Dmitry K. Morits, Pavel M. Voroshilov, Michael E. Guzhva, Pavel A. Belov, Yuri S. Kivshar
description:this paper consists of covering the cell by nano antennas with very small thickness which will improve the light trapping capacity of solar cell.
description:Wang, W., Lin, A.S. and Phillips, J.D., 2009. Intermediate-band photovoltaic solar cell based on ZnTe: O. Applied Physics Letters, 95(1), p.011103.
description:oxygen doped ZnTe is applied to jucnction diode and improved all parameters
43:link:"http://www.nrel.gov/docs/fy15osti/65120.pdf" reference:Baghdasaryan, H.V., Knyazyan, T.M., Hovhannisyan, T.T., Mardoyan, G.R. and Marciniak, M., 2016, July. Wavelength-scale analysis of influence of chirped DBRs on optical characteristics of multinanolayer photovoltaic cells. In Transparent Optical Networks (ICTON), 2016 18th International Conference on (pp. 1-5). IEEE.
descriptio:by reduceing the thickness of ARC,parameters changed
description:porous sillicon layer is formed with electro chemical etching,and then properties are improved
reference:Lee, Y.L. and Lo, Y.S., 2009. Highly Efficient Quantum‐Dot‐Sensitized Solar Cell Based on Co‐Sensitization of CdS/CdSe. Advanced Functional Materials, 19(4), pp.604-609.
description:Cadmium sulfide (CdS) and cadmium selenide (CdSe) quantum dots (QDs) are sequentially assembled onto a nanocrystalline TiO2 film to prepare a CdS/CdSe co-sensitized photoelectrode for QD-sensitized solar cell application.
description:a solar cell is manufactured with TiO2 As ARC in Sol-gel method whose eiificiency is lesss than normal solar cell
description:3 layer of ARCs developed on solarcell to get better peformance