The use of HfO2 in a point contact concept for front interface passivation of Cu(In,Ga)Se2 solar cells
The use of HfO2 in a point contact concept for front interface passivation of Cu(In,Ga)Se2 solar cells
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DOI：
10.1016/j.solmat.2019.03.009
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发表时间：
2019-06-15
影响因子：
6.9
通讯作者：
Tiwari, Ayodhya N.
中科院分区：
文献类型：
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作者：
Lockinger, Johannes;Nishiwaki, Shiro;Tiwari, Ayodhya N.
我们报道了在Cu(In,Ga)Se-2 （CIGS）太阳能电池的前界面上使用高带隙金属氧化物的点接触概念，以减少界面复合。采用原子层沉积法（ALD）在CIGS表面镀上高电阻HfO2。通过时间分辨光致发光（TRPL）、电子束感应电流（EBIC）和电容电压（C-V）测量，研究了HfO2对CIGS表面钝化的影响。比较了两种点接触形成的结构方法，一种是光刻自顶向下的方法，另一种是以NaCl为模板的简单自底向上的方法。前一种方法采用等离子体蚀刻步骤，当应用于CIGS表面时，发现会降低太阳能电池的性能。该模板方法省去了溅射，并允许在不影响开路电压（V-OC）的情况下对厚度达10 nm的HfO2进行图案化。EBIC显示，由于HfO2涂层，载流子收集得到改善，并且观察到长期稳定的PL衰减。然而，在所研究的参数范围内，与HfO2的点接触概念对CIGS太阳能电池的性能没有显著影响。
We report on the use of a high bandgap metal-oxide at the front interface of Cu(In,Ga)Se-2 (CIGS) solar cells in a point contact concept for reduced interface recombination. Highly resistive HfO2 is applied on the CIGS surface by atomic layer deposition (ALD). Aspects of the surface passivating effect of HfO2 on CIGS were investigated by time-resolved photoluminescence (TRPL), electron beam induced current (EBIC) and capacitance-voltage (C-V) measurements. Two structuring methods for point contact formation are compared, a lithographic top-down and a simple bottom-up approach using NaCl as template. The former method employed a plasma etch step which was found to degrade the performance of solar cells when applied on the CIGS surface. The template method omitted sputtering and allowed patterning of HfO2 up to 10 nm thickness without adversely impacting the open-circuit voltage (V-OC). EBIC revealed an improved carrier collection due to the HfO2 coating and a long term stable PL decay was observed. Yet, the point contact concept with HfO2 was not significantly influencing the performance of a CIGS solar cell for the investigated parameter range.