晏迪博士-多晶硅金属钝化接触是否能成为下一代高效硅电池的主流技术？

Polysilicon pasivated junctions: the next technology for silicon solar cells? (多晶硅金属钝化接触是否 能成为下一代高效硅电池的主流技 术？） Di Yan （晏迪） The department of Electrical and Electronic Enginering 1 2 Our group Group leader: •Dr. James Bullock Group member: •Dr. Di Yan •Mr. Wei Yan •Mr. Jesus Ibara Michel •Mr. ShifangWang Main research areas:(研究课题) •Photovoltaic materials (光伏材料): •Exploring new materials for solar cels, such as carier-selective passivated contacts and dielectric layers for surface pasivations. •Optoelectronic devices:（光学器件) •2D material basedphotodetectors and transistors Content 3 Introduction: •Fundamentals about silicon solar cels（硅电池的基本原理） •The status of silicon solar cels with poly-Si pasivated contacts（基于poly-Sicontact的硅电池的概述） Poly-Si pasivated contacts technologies（poly-Sicontacts工艺） •Diferent approachesPerformances（不同的工艺以及不同工艺的poly-Sicontacts的性能） Industrial aplication（工业化） •Current chalenges（现有的挑战）: industrial proces combability and cost analysis（现有电池工业的 兼容问题和制造成本） •Device architectures（基于poly-Sicontact的电池结构） Conclusion Theoretical values can be achieved by silicon:（硅电池的理 论值） J sc(max) = 43.3 mA/cm 2 V oc(max) = 760 mV V mpp = 70 mV Eficiency (%) = 29.4 % Carier-selective contacts/junction: （载流子选择性接触） It is esential have a prefered route for electrons and holes towards opposite metal terminals. Doped siliconsare most comon materials: •N-type silicon works as electron contact •P-type silicon works as hole contact Introduction e - h + h + h + h + h + h + e - h + h + E Fn E C E V e - h + Surface-pasivating “skin” e - e - e - e - e - e - From Cuevas et al. EUPVSEC 2018 electron contact 5 Introduction Thre main carier-selective contacts/junctions:（在硅电池里的主要选择 性接触） •Dopant Difusion: high J o and low ⍴ c ; localised regions stil have high J o . (Jo = 28 –80 fA/cm2) •Poly-Si: low Jo and low pc. (Jo = 6 -20 fA/cm2) •A-Si: low Jo and TCO required (low temperature proces) for low pc. (Jo = 2 –5 fA/cm2) Poly-Si show a high degre of procesing compatibility with conventional dopant difusion technologies.（poly-Si技术跟现有的工业工艺 有很高的兼容性） 6 Introduction The involvement of the poly-Si pasivated contacts can help us to reach higher eficiency silicon solar cels.(poly-Si能保证高效的硅太阳能电 池，现在的硅电池的记录保持者都基于poly-Sicontacts） •Above 26% on the smal area silicon solar cels (ISFH and Fraunhofer ISE) •~ 24.9% on the industrial large scale solar cells (Jinko solar); The International Technology Roadmap for PV (ITRPV) predicts that the uptake of poly-Si junction architectures wil continue to grow over the next decade, almost 35% of the entire market, reaching industry average eficiencies of 24% and 24.5% for p-and n-type substrates by the year 2030.（ITRPV展望在2030年将有35%的硅太阳能电池将 基于poly-Sicontacts） 7 Poly-Si pasivated contacts technologies Main steps to fabricate poly-Si pasivated contacts: （poly-Sicontacts工艺的基本步骤） 1)Growth or deposition of a thin interfacial layer, generaly SiO x ;（绝缘层二氧化硅的形成） 2)Deposition of a silicon/silicon compound film;（多晶硅薄膜以及硅的化合物的沉积） 3)Incorporation of dopants into the silicon film;（掺杂） 4)Recrystalization of the silicon and activation of the dopants;（硅薄膜的晶体化以及掺杂的激活） 5)Hydrogenation.（氢钝化） Poly-Si pasivated contacts technologies 8 The Jo and its coresponding VULof poly-Si contacts with diferent approaches. (在不同工艺下的复合电流以及其对应的理想开压） Jo 735 mV) was achieved for poly-Si contacts using a range of aproaches. Independent of the deposition/doping technique used. （性能在不同的工艺环境下表现的很稳定） Majority data are on the LPCVD with ex-situ thermal oxide and subsequent thermal difusion proces. This is widely used in industries. （研究 主要集中于产业化的LPCVD和热扩散的工艺） A consistent trend of lower J 0 for phosphorus- doped, versus boron-doped. Due to the segregation and difusion coeficients of dopants in poly-Si layers and the SiOxlayers. （n型比p型 有较低的复合电流） 9 Industrial perspectives TheimpactofthethicknesonJsc:(厚度对于光学 性能的影响） •Increasingpoly-SithicknessesincreasesJ sc loses duetoits“parasiticabsorption”. •J sc of0.4-0.5mA/cm 2 per10nmforfront. •~0.3-0.5mA/cm 2 fora140nmthickpoly-Silayer asrearside. •Usingwidebandgapmaterials,e.g.SiCxorSiOx. Theimpactofscreen-printedmetallization proces:（金属接触对于复合的影响） •TendstohavehighJoaftermetalizationproces, ~100timeshigher. •Metalpasteand/orusingothermetalization methods,e.g.plating. Theimpactofsurfacetexturing:（硅表面对于复 合的影响） •TheJoofpoly-Sijunctionsontexturedsurfaces isapproximately10timeshigherthanthaton planar(100)surfaces. •Aslightofetchingoftipsandoptimizingthe oxidegrowthanddopingprofiles. 10 Industrial perspectives According to a recent study by Kafleet al., the cost of an n-type solar cel a rear n + poly-Si layer is 18% higher than a p-type PERC cel. （poly-Sin型电池的成本比 p型PERC电池的成本高18%） In adition to the costs of boron difusion and LPCVD Si film deposition, which are relatively low, the cost diference is mainly due to the use of n-type wafers instead of p-type and to the cel’s metalisation.（主要 的成本来源于金属化和n型硅片） In terms of $/W, this cost gap can be compensated for if PV modules made with poly-Si junctions have at least a 0.4% higher conversion efficiency than conventional PERC modules.（但是高效的poly-Si的n型 的成本 接 于p型PERC的 ） 11 Future perspectives: device architectures Tandem solar cells:（ 于硅电池的 电池 ） •Poly-Si contacts have excelent thermal stability. (较 的热稳定性） •Posibilitiesofusingother metal oxide contacts in combination with poly-Sitoformthe “recombination layer”, which both simplifies the fabrication and reduces parasitic absorption（在 成 电池中的 复合 于 材料 合的 能性 C 的应 ） Single junction solar cels:（ 硅电池） •IBC •P-type PERC celswithrearjunction（ 的p型PERC 电池） •N-type solar cels（n型 面电池） •P-type solar cels with localised poly-Si contacts（p型 电池 的poly-Si on ） 12 Conclusion: •Siliconsolarcellarchitecturesfeaturingpoly-Sibasedjunctionsarepoisedtobecomethenextevolutionarystepfor mainstreamsiliconphotovoltaics,pavingthewaytowardsanaverageindustrycellefficiencyof25%overthenext decade.（poly-Sicontact技术将是下一代25%转换效率的硅电池主流技术） •Thelargelyuniformresultsacrosmultiplepoly-Sifabricationproceduresspeakstotheversatilityoftheapproachand thepotentialfortransfertolow-costtechniques,whichhasbecomeadominantresearchfocus.（poly-Sicontact对 于不 工艺的 性 下一步的工艺研究 将 以 成本 主要 ） •However,severalchallengesremaintobemet,mostassociatedwiththecostandperformanceofpoly-Sijunction metalization.Thesechallengesarelargelyresponsibleforthecurent~18%highermanufacturingcostofpoly-Si junctioncellscomparedtoPERC.（ 很多的 成本高于现有的 技术 ¡化¢ 光学性 是下一步的研究 ） •Severalcandidatecellarchitecturesarebeingexploredwithbothnandp-typesubstrates,mostofwhichoffera~1% absoluteliftinefficiencyoverthecurentindustrydominatingPERCtechnology.（poly-Sicontact£⁄ ¥多的电 池的ƒ§的currency1 性 效率将“现有的 电池的效率高«%） •Poly-SijunctionsprovideapathwayforupgradingcurentPERCtechnology,anditislikelythatoverthenextdecade botharchitectureswilldevelopfurther,alongsideothersolarcelltechnologies.（poly-Si技术将是 技术的‹› fi 不fl的将 跟 –电池技术†‡在光· ¶） Thankyou谢谢 Email: di.yan@unimelb.edu.au