Abstract In order to analyze why the CIGS (CuInGaSe2) - based solar cells efficiency decrease for wide band gap (high Ga content), we have performed a series of samples by PVD using the three stage process. The average compositions of our solar cells range from x = 0 to x = 0.88, as measured by X-ray diffraction. An important feature of this process is to create a double Ga gradient into the absorber, which contributes to improve efficiencies, and this has a major impact on the determination of the sample composition from x-ray diffraction data. We have developed a model in order to assess this impact and question the validity of the compositions extracted from x-ray data. This model allows to get some information about gradient shapes. Using our model, we have obtained some insights on the evolution of the gallium gradient in samples with increasing Ga content, and we determine that this gradient is less pronounced when increasing the amount of gallium. It is a well known fact that this gradient assists the extraction of photocreated carriers, and the modifications of the gallium profile that we have determined may explain, for some part, the degradation of solar cells efficiency for high gallium compositions.

中文翻译：

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通过 X 射线衍射分析 Cu(In1-xGax)Se2 吸收剂中的镓梯度

摘要 为了分析基于 CIGS (CuInGaSe2) 的太阳能电池在宽带隙（高 Ga 含量）下效率降低的原因，我们使用三阶段工艺通过 PVD ​​进行了一系列样品。通过 X 射线衍射测量，我们太阳能电池的平均成分范围从 x = 0 到 x = 0.88。该过程的一个重要特征是在吸收剂中产生双 Ga 梯度，这有助于提高效率，这对根据 X 射线衍射数据确定样品成分具有重大影响。我们开发了一个模型来评估这种影响并质疑从 X 射线数据中提取的成分的有效性。该模型允许获取有关渐变形状的一些信息。使用我们的模型，我们已经获得了一些关于随着 Ga 含量增加的样品中镓梯度演变的见解，并且我们确定当增加镓的量时，这种梯度不那么明显。众所周知，这种梯度有助于提取光产生的载流子，我们确定的镓分布的修改可以在某种程度上解释高镓成分的太阳能电池效率的下降。