高效、低成本太阳电池的研究

【作者】 郜小勇；

【导师】 卢景霄；

【作者基本信息】 郑州大学 ， 凝聚态物理， 2001， 硕士

【摘要】 进一步提高效率、降低成本是光电池今后发展的趋势。不论是单晶体硅电池还是薄膜电池都面临着产业化的问题。目前实验室里的高效硅太阳电池的效率已接近25％，提高的额度有限。因此下一步硅太阳电池的发展重点放在大幅度降低硅太阳电池的成本和产业化上来。如何将实验室高效硅太阳电池的制备工艺经过适当简化，应用到工业生产上去是需要迫切解决的问题。本论文从这个角度出发，着重研究了适合工业生产的刻槽埋栅电池的制备技术和廉价SSP衬底上多晶硅薄膜电池的制备技术。 本论文总体上分为两大部分。第一部分着重适合工业化生产的刻槽埋栅电池的制备技术的研究。针对机械刻槽电池的特点，采用间距1mm的正面电极图形和掺杂浓度适中的发射区设计；正面钝化工艺，采用半导体工艺常用但在太阳电池工艺上很少采用的干—湿—干氧化法，大大缩短了氧化时间，降低了硅片由于长时间高温过程造成的损伤，降低了生产成本，提高了生产效率。实验证明，由干—湿—干氧化法制备的氧化层的厚度和质量都很好的满足了机械刻槽电池的工艺的要求；背面采用全铝背场结构，实验证明对电阻率较高的材料铝背面电场的确能提高载流子的收集率，降低背表面的少子复合，从而提高了太阳电池的填充因子和电池效率。在合理设计和简化工艺的基础上，制作的太阳能级硅材料的φ38mm的机械刻槽电池的效率达到7.4％。 第二部分重点对低成本SSP衬底上多晶硅薄膜电池的制备技术做了研究。Fraunhofer研究所作过统计，在体硅电池的总成本中，材料的成本占了50％，技术只占了15％。因此在硅太阳电池效率提高额度有限的情况下，降低材料的成本成为必然。多晶硅薄膜电池因具有这方面的优势而被受关注。SSP作为一廉价、耐高温衬底，应用到多晶硅薄膜电池具有美好前景。本部分针对SSP（SiliconSheet from Powder）衬底（由中国硅粉拉制）杂质含量高的特点，为防止多晶硅薄膜生长过程中，衬底杂质对薄膜造成不良影响，在电池的设计中采用了P⁺阻挡层和快速生长技术。不仅减小了衬底杂质的负面影响，而且有效增大了多晶硅薄膜的晶粒尺寸。试验室制备的1cm²低纯SSP衬底上的多晶硅薄膜电池的效率达到了4.5％。认我们认为P⁺阻挡层对衬底杂质的阻挡效果不如SiO₂，采用SiO₂打孔结构辅助减反射膜和钝化技术，电池效率接近8％的世界最高水平极有可能。更多还原

【Abstract】 Ab8tractThe futhe M fOr the developmen of the solar cell is tO hather twve the effic~ andlower the cost. At Prdent, the efficienCy of the high-etheien soar Cell Inade in labondory hasbeen close to 25% 8nd the extra seale is alrePdy boited. TherfOre, thc gh wtis bold bepaid on the low coSt and industrialhation. The Urgeni pndem to be soved is hOw to s~fy thePngess Of the high-effichay solar cell in laboraories and 8pply tO Mal Nn.According to the idea, the mper studles the ProduChon theogy of the me-cally ~bdried contaCt so1ar ce11 and the PrePaboon ednology of the multi-crystelire thin fi1m solar ce1lon the inexPensive SSP subStrae.The paPer is taken intO two pes Wg to the cPPtent, The firS tw ndes theproduction techno1ogy of the mechaCaly grooved buried contat solar cen. The lmmWdefmpers and dmp endtter with dmp junction and mediUm cboer’s densty are adoed in the dsstriof the solar cell. The dry okidatlon-wet okidation wt okidation PrOCeSs, often used .in thesendondctor produCtiOn. is adoPted to for and back schce P8Ssivation. The tAne of thermaoxidtion is Wly shortened and the daInages caused by 1ong tAne high pee processddriiM. The eXPenment Proves the requmeent of the device and the PrOcess in the qnd1ityand the thlcboss of the silicon oxidation layer is well met. The na alaminum back whce fieldsboctUre is adOPted whlch redly hoproves the collecting efficiency of the cwhers, lowers the backWe recombinbo and driPrOves the packing factor and the efficierey of the solar cell. Basedon the ProPer design and stwle Process, the efficiency of the mecbocally grooved buriedcOnact solar cel1 on the sun gude sll1con nake withch38mm gain5 as The converslonefficiency of l4% is POssible if the e1ectrOless plating Process and the Ohhac contact aretheroved.The otber part StUdied the Preparation technology of the multi-cryStalline dri film cell on theineWsi’e SSP SLthstrate. FraWfer InStitute once gave the stahstics tha the material costcomes to 50% of the net cost while the technique only comes to l5%. So to lower the material coStis ncccssary The multi-crystaline thin film solar cel1 is Paid attention to because of itS advantagein this reSPect. SSP, an ineXPensive and high-teInPeate Substrate, is ProsPective to be used in thethin fibo ceIl The P+ bAner l8yer 8nd raPid growh teChnology are adoPted tO restIain the xadverse effect on the thin f1bo caused by the wtties in the SSP tw the process of the2groWth of multi-crystal1ine thin film. The raPid growth teChnology not only decease the advereeeffect on the thin fiIm but increase the guin size of multi-coptalline thin filIn. The efficiency ofthe multi-crystaline thin fi1m solar cell on the l cm2 SSP substrate gains 4.5%. we think P+boerlayer -is inferior to SiO2 layer and the efficlency of the ce1l will approach and even exceed theefficiency of 8%, the world record, if the SiO2portratcd structUre and passiVation of edce andgrain boundary are adoPted.更多还原