Abstract Sodium is typically used during the synthesis of kesterite thin films to enhance the performance of solar cells. As sodium tends to affect grain growth and morphology, it is difficult to analyse solely the electronic effects of sodium as dopant. To decouple the structural and electronic effects from each other, two processes were designed in this work to successfully incorporate sodium into a vacuum-processed Cu2ZnSnSe4 absorber without changing the morphology. A thin layer of NaF is deposited before precursor deposition (Pre-NaF) or after absorber synthesis to undergo a post deposition treatment (NaF-PDT). While composition and distribution of matrix elements remain unchanged, the sodium concentration is increased upon sodium treatment up to 140 ppm as measured by inductively coupled plasma mass spectrometry. X-ray photoelectron spectroscopy showed that the surface composition was not altered. Within its detection limit, sodium was not present at the absorber surface. For a Pre-NaF sample measured with atom probe tomography a sodium concentration of 30 ppm was measured in a grain, suggesting that sodium might segregate at grain boundaries. The additional sodium content in the film leads to an increased acceptor concentration, which results in improved open-circuit voltage and fill factor.

中文翻译：

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从钠处理的锌黄锡矿薄膜太阳能电池的形态变化中解耦光电特性

摘要钠通常用于合成锌黄铜矿薄膜以提高太阳能电池的性能。由于钠往往会影响晶粒生长和形态，因此很难仅分析钠作为掺杂剂的电子效应。为了将结构和电子效应相互解耦，这项工作设计了两种工艺，以成功地将钠加入真空处理的 Cu2ZnSnSe4 吸收剂中，而不会改变形态。在前体沉积之前 (Pre-NaF) 或在吸收剂合成之后沉积一层薄薄​​的 NaF，以进行沉积后处理 (NaF-PDT)。虽然基质元素的组成和分布保持不变，但通过电感耦合等离子体质谱法测量，钠浓度在钠处理后增加至 140 ppm。X 射线光电子能谱表明表面组成没有改变。在其检测范围内，吸收剂表面不存在钠。对于用原子探针断层扫描测量的 Pre-NaF 样品，在晶粒中测得的钠浓度为 30 ppm，这表明钠可能在晶界处分离。薄膜中额外的钠含量会导致受体浓度增加，从而提高开路电压和填充因子。