不同环境下硫化镉/铜基薄膜异质结退火对太阳电池性能调控  

Regulation of solar cell performance by cadmium sulfide/copper-based thin film heterojunction annealing under different atmospheres

作　　者：刘慧桢 刘蓓[1,2,3] 董家斌 李建鹏[1,2,3] 曹子修 刘越 孟汝涛[1,2,3] 张毅 Liu Hui-Zhen;Liu Bei;Dong Jia-Bin;Li Jian-Peng;Cao Zi-Xiu;Liu Yue;Meng Ru-Tao;Zhang Yi(Solar Energy Conversion Center,Institute of Optoelectronic Thin Film Devices and Technology,NanKai University,Tianjin 300350,China;Tianjin Key Laboratory of Optoelectronic Thin Film Devices and Technologies,Tianjin 300350,China;Engineering Research Center of the Ministry of Education for Thin Film Optoelectronics Technology,Tianjin 300350,China)

机构地区：[1]南开大学,光电子薄膜器件与技术研究所,太阳能转换中心,天津300350 [2]天津市光电子薄膜器件与技术重点实验室,天津300350 [3]薄膜光电子技术教育部工程研究中心,天津300350

出　　处：《物理学报》2023年第8期330-340,共11页Acta Physica Sinica

基　　金：国家重点研究发展计划(批准号:2018YFB1500200);国家自然科学-云南联合基金重点项目(批准号:U1902218)资助的课题.

摘　　要：高效铜基薄膜太阳电池通常采用无机n型半导体材料CdS作为缓冲层,因此,缓冲层与吸收层之间的界面质量和能带匹配对载流子的收集利用至关重要.在优化CdS基础工艺的基础上,在含硫气氛下对硫化镉/铜基薄膜异质结进行退火的策略进一步提高CdS薄膜质量,并将其应用到铜基太阳电池,调控铜基薄膜电池p-n异质结能带匹配.研究表明,CdS薄膜在含硫的惰性气氛中退火可以有效提高CdS薄膜的结晶质量并抑制CZTS/CdS异质结界面的非辐射复合,器件的开路电压得到大幅提升,最高可达718 mV.在器件效率方面,基于溅射法的CZTS太阳电池效率从3.47%提升到5.68%,约为不退火处理的2倍.该研究为铜基薄膜太阳电池器件实现高开路电压提供了可靠的工艺窗口.同时,有力地说明了退火气氛选择对于CdS质量以及CZTS/CdS异质结能带匹配的重要性,除了界面互扩散以外,对薄膜材料组分及其结晶性等均实现了调控.Efficient copper based thin film solar cells usually use inorganic n-type semiconductor material CdS as the buffer layer.Therefore,the interface quality and energy band matching between the buffer layer and the absorption layer are crucial to the collection and utilization of carriers.Heat treatment can promote the mutual diffusion of interface elements,the migration of ions in the material,and the change of defect state,and the appropriate temperature will change the Cu-Zn ordering degree in the absorption layer,so as to improve the efficiency of the solar cells.Based on the optimization of CdS basic process,the strategy of annealing CdS/copper-based thin film heterojunction in sulfur atmosphere further improves the quality of CdS thin film,and is applied to copper-based solar cells to regulate the p-n heterojunction energy band gap matching of copper-based thin film cells.The results show that the annealing of CdS thin film in sulfur-containing inert atmosphere can effectively improve the crystal quality of CdS thin film and inhibit the non-radiative recombination loss caused by defect trapping at the interface of CZTS/CdS heterojunction,and the open-circuit voltage of the device can significantly increase to 718 mV.In addition,annealing CZTS/CdS heterojunction in S/Ar atmosphere can effectively improve the p-n heterojunction energy band gap matching,which not only improves the electron transmission,but also reduces the carrier recombination,thus improving the V_(oc) and FF of the device.Besides,the oxygen element in CdS film can be replaced by sulfur element in sulfur atmosphere to improve the quality of CdS film,and thus enhancing the short-wave absorption of solar cell device.Therefore,in terms of device efficiency,the efficiency of CZTS solar cell based on sputtering method increases from 3.47%to 5.68%,which is about twice that of non-annealing treatment.Its device structure is Glass/Mo/CZTS/CdS/i-ZnO/Al:ZnO/Ni/Al,providing a reliable process window for copper based thin film solar cell devices to achieve h

关 键 词：铜基薄膜太阳电池 硫化镉缓冲层 退火气氛 硫化镉/铜基薄膜异质结 

分 类 号：TM914.4[电气工程—电力电子与电力传动]