Influence of iron on defect concentrations and device performance for Cu(In,Ga)Se2 solar cells on stainless steel substrates
Influence of iron on defect concentrations and device performance for Cu(In,Ga)Se2 solar cells on stainless steel substrates
复制标题
DOI：
10.1002/pip.2260
复制
发表时间：
2012-08-01
影响因子：
6.7
通讯作者：
Unold, Thomas
中科院分区：
文献类型：
--
作者：
Eisenbarth, Tobias;Caballero, Raquel;Unold, Thomas
研究了用共蒸发法在柔性钢箔衬底上制备的Cu（In，Ga）Se2（CIGSe）薄膜太阳电池。铁从钢箔衬底材料扩散到CIGSe吸收层的研究，通过二次离子质谱（西姆斯）为不同的最大吸收体生长温度和太阳能电池背接触配置。吸收体生长温度的优化，在背接触处的扩散阻挡层的引入，以及钠掺杂的调整导致器件效率高于14%。通过导纳测量的缺陷光谱示出了在CIGSe吸收层中的Fe含量的深缺陷浓度的明确的相关性和钠掺入和净载流子浓度之间的相关性。发现过多的Na支持Fe的扩散，引起深缺陷浓度的增加。铁诱导的深缺陷，形成一个广泛的受体型缺陷带在0.44？电子伏特以上的价带最大值被认为是本体复合的原因，限制了这些太阳能电池中的器件性能。版权所有（c）2012约翰威利父子有限公司
Thin film Cu(In,Ga)Se2 (CIGSe) solar cells deposited on flexible steel foil substrates by coevaporation are investigated. Iron diffusion from the steel foil substrate material into the CIGSe absorber layers is studied by secondary ion mass spectroscopy (SIMS) for different maximum absorber growth temperatures and solar cell back-contact configurations. The optimization of the absorber growth temperature, the introduction of a diffusion barrier layer at the back contact, and the adjustment of the sodium doping lead to device efficiencies above 14%. Defect spectroscopy by means of admittance measurements shows a clear correlation of the deep defect concentration with the Fe content in the CIGSe absorber layer and a correlation between the sodium incorporation and the net carrier concentration. It is found that too much Na supports the diffusion of Fe, inducing an increased deep defect concentration. The Fe-induced deep defects, which form a broad acceptor-type defect band at 0.44?eV above the valence band maximum, are identified as the cause of bulk recombination, limiting the device performance in these solar cells. Copyright (c) 2012 John Wiley & Sons, Ltd.