Complete Report - University of New South Wales

ARCPHOTOVOLTAICSCENTRE OFEXCELLENCE2010/11ANNUAL REPORTSimulated Voc of a poly-Si solarcell (2.2 µm thick n-type absorber,Jsc 27 mA/cm 2 ) in which bothshallow bands recombination anddeep level recombination at grainboundaries (with electrostaticfluctuations) occur.Figure 4.4.1.38The effect of recombination via deep levelsat charged defects is to place an upperlimit on the minority carrier lifetime (thusthe cell Voc). Figure 4.4.1.38 shows Vocsimulation results of poly-Si solar cellswhere two recombination processes inthe absorber, both via shallow bands andvia deep levels, taking place in parallel.Above 1x10 16 cm -3 doping, the Voc is fairlyconstant and approaches the 485 mVlimit corresponding to the case whereonly shallow band recombination occurs.Below 1x10 16 cm -3 doping, deep levelrecombination becomes influential to thedevice performance eroding the Voc by about 21mV when the doping reaches 1x10 15 cm -3 . Thus, inthe practically significant dopant concentrationrange of 5x10 15 ~5x10 16 cm -3 , an immediatechallenge to consistently raising the Voc above 500mV is to reduce the dislocation density to belowthe 1x10 9 cm -2 level. If and when this is achievedthe next step to even higher Voc is minimisation ofcharged defects likely associated with impurities.4.4.1.11 References4.4.1.1 M.A. Green, “Polycrystalline silicon on glassfor thin-film solar cells”, Applied Physics A: 96,p. 153, 2009.4.4.1.2 A. G. Aberle, “Fabrication and characterisation ofcrystalline silicon thin-film materials for solar cells”,Thin Solid Films, 26, p. 511, 2006.4.4.1.3 P. A. Basore, Proceedings of the 21st EUPVSEC, p.544, Dresden, Germany, 2006.4.4.1.4 M. Keevers, T.L. Young, U. Schubert, R. Evans,R.J. Egan and M.A. Green, “10% Efficient Csgminimodules:, Proceedings of the 22nd EUPVSEC,p. 1783, Milan, Italy, 2007.4.4.1.5 G. Jin, P. I. Widenborg, P. Campbell, S. Varlamov,“Lambertian matched absorption enhancementin pecvd poly-Si thin film on aluminiuminduced textured glass superstrates for solar cellapplications”, Progress in Photovoltaics: Researchand Application, 2010, v. 18, pp. 482-589.4.4.1.6 Z. Ouyang, S. Pillai, F. Beck, O. Kunz, S. Varlamov, K.R. Catchpole, P. Campbell, M. A. Green, “EffectiveLight Trapping in Polycrystalline Silicon Thin-filmSolar Cells by Means of Rear Localised SurfacePlasmons”, Appl. Phys. Lett., 2010, v. 96, 261109.4.4.1.7 P. I. Widenborg, G. Jin, P. J. Gress, and S. Varlamov,“High rate 13.56MHz PECVD a-Si:H depositions forSPC poly-Si thin film solar cells”, Proceedings of the24th EUPVSEC, Hamburg, 2009.4.4.1.8 Z. Ouyang, O. Kunz, A. B. Sproul, S. Varlamov,“Influence of the absorber doping for p-typeevaporated polycrystalline silicon thin-film solarcells on glass, J. Appl. Phys., 2011, 109, 060104.4.4.1.9 P.J. Gress, P.I. Widenborg, S. Varlamov, A.G. Aberle,Wire bonding as a cell interconnection techniquefor polycrystalline silicon thin-film solar cells onglass”, Progress in Photovoltaics: Research andApplications, 2010, v. 18, pp. 221-228.4.4.1.10 P.I. Widenborg, N. Chuangsuwanich, A.G. Aberle,Glass texturing, Patent AU2004228064A1.4.4.1.11 P.I. Widenborg, A.G. Aberle, “PolycrystallineSilicon Thin-Film Solar Cells on AIT-Textured GlassSuperstrates”, Advances in Optoelectronics, 2007,article ID 24584.4.4.1.12 P.I. Widenborg, S.V. Chan, T. Walsh, and A.G. Aberle,“Thin-Film Poly-Si Solar Cells on AIT-textured Glass– Importance of the Rear Reflector”, Proceedings ofthe 33rd IEEE PVSC, San-Diego, 2008.4.4.1.13 O. Kunz, Z. Ouyang, S. Varlamov, and A.G. Aberle,“5% efficient evaporated solid-phase crystallisedpolycrystalline silicon thin-film solar cells”, Progressin Photovoltaics: Research and Applications, v. 17,p. 567, 2009.4.4.1.14 O. Kunz, Z. Ouyang, J. Wong, and A.G. Aberle,“Advances in evaporated solid-phasecrystallizedpoly-Si thin-film solar cells on glass(EVA)”, Advances in Optoelectronics, 2008,article ID 532351.4.4.1.15 O. Kunz, J. Wong, J. Janssens, J. Bauer, O.Breitenstein, A.G. Aberle, “Shunting Problems Dueto Sub-Micron Pinholes in Evaporated Solid-PhaseCrystallised Poly-Si Thin-Film Solar Cells on Glass”,Progress in Photovoltaics, 2009, v. 17, pp.35-46.4.4.1.16 H. Cui, G. Jin, M. Wolf, P. Campbell, M. Geen,“Enhanced Absorption of SPC Poly-Si Thin Filmson Aluminium Induced Textured (AIT) Glass withSubmicron Texture Feature Size”, Proceedings ofthe 25th EUPVSEC, Valencia, Spain, 2010.4.4.1.17 S. Varlamov, Y. Tao, J. Wong, O. Kunz, R. Egan,“Crystallisation kinetics of e-beam evaporated Sifilms and its effects on poly-Si film and solar cellproperties”, 25th EUPVSEC, Valencia, Spain, 2010.4.4.1.18 Y. Tao, S. Varlamov, J. Wong, O. Kunz, R. Egan,“Effects of SPC temperature on properties ofevaporated poly-si thin films and soalr cells”, 35thIEEE PVSC, Hawaii, USA, 2010.52