Many technologies deposit thin films on inexpensive substrates, resulting in small grains due to classic nucleation and grain growth theory. For example, state-of-the-art solar cells are made by depositing CdSeTe and CdTe layers on inexpensive glass coated with nanocrystalline transparent conducting oxides (TCOs), like SnO₂. Characteristically, the grain size of these films is on the order of the film thickness, i.e. a few microns. CdTe small-grain films have poor electro-optical properties and require CdCl₂ passivation which fails to fully passivate grain boundaries, causes carrier compensation, and prevents implementing other II–VI alloys and materials to improve performance. Here, we present a method to increase grain size to 1 mm in CdSe_xTe_1−x thin films deposited on glass/TCO substrates without CdCl₂ treatment. The colossal grain growth is driven by mechanisms distinct from classic nucleation, grain growth, and Ostwald ripening and only occurs at low selenium content (x ∼ 0.1). We also demonstrate how these films can serve as templates for subsequent large-grain epitaxy of other compositions like CdTe, again without exposure to CdCl₂. The results open new paths for thin film solar cell technology, and thin film devices in general.

由于经典的成核和晶粒长大理论，许多技术都在廉价的基板上沉积薄膜，导致晶粒细小。例如，通过在便宜的玻璃上沉积CdSeTe和CdTe层来制造最先进的太阳能电池，该玻璃上涂有纳米晶透明导电氧化物（TCO），如SnO ₂。在特征上，这些膜的晶粒尺寸为膜厚度的数量级，即几微米。CdTe小晶粒薄膜的电光性能很差，并且需要CdCl ₂钝化，而钝化不能完全钝化晶界，不会引起载流子补偿，并妨碍使用其他II-VI合金和材料来提高性能。在这里，我们提出一种将CdSe _x Te中晶粒尺寸增加到1 mm的方法未经CdCl ₂处理的_1-x薄膜沉积在玻璃/ TCO基板上。的巨大的晶粒生长是通过从经典成核，晶粒生长不同的机制驱动，奥斯特瓦尔德熟化和只发生在低的硒含量（X〜0.1）。我们还演示了如何将这些薄膜用作其他组合物（如CdTe）随后大晶粒外延的模板，而又无需暴露于CdCl ₂。结果为薄膜太阳能电池技术和一般的薄膜器件开辟了新的道路。