Thin-film solar modules based on cadmium telluride (CdTe) technology currently produce the world's lowest cost solar electricity. However, the best CdTe modules now contain a cadmium selenium telluride (CST) alloy at the front of the absorber layer. Despite this, research characterizing the behavior of selenium in alloyed CdTe devices is currently very limited. Here we employ advanced secondary ion mass spectrometry measurements to map the three-dimensional distribution of selenium in a graded CST/CdTe device for the first time. We find significant interdiffusion of selenium between the CST and CdTe layers in the cell, primarily out of the CST grain boundaries and up into the CdTe grain boundaries and grain fringes above. This results in significant lateral variations in selenium concentrations across grains and hence also lateral fields, which we estimate using the measured selenium concentrations.

中文翻译：

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高效硒级碲化镉太阳能电池中硒和氯分布的三维成像

目前，基于碲化镉 (CdTe) 技术的薄膜太阳能模块可生产世界上成本最低的太阳能电力。然而，现在最好的 CdTe 模块在吸收层的前部包含碲化镉 (CST) 合金。尽管如此，表征硒在合金碲化镉器件中的行为的研究目前非常有限。在这里，我们首次采用先进的二次离子质谱测量来绘制分级 CST/CdTe 设备中硒的三维分布。我们发现电池中 CST 和 CdTe 层之间的硒显着相互扩散，主要是从 CST 晶界向外扩散到上面的 CdTe 晶界和晶粒边缘。这导致晶粒间硒浓度的显着横向变化，因此也导致横向场，