II–IV–V₂ materials, ternary analogs to III–V materials, are emerging for their potential applications in devices such as LEDs and solar cells. Controlling cation ordering in II–IV–V₂ materials offers the potential to tune properties at nearly fixed compositions and lattice parameters. While tuning properties at a fixed lattice constant through ordering has the potential to be a powerful tool used in device fabrication, cation ordering also creates challenges with characterization and quantification of ordering. In this work, we investigate two different methods to quantify cation ordering in ZnGeP₂ thin films: a stretching parameter calculated from lattice constants , and an order parameter determined from the cation site occupancies (S). We use high resolution X-ray diffraction (HRXRD) to determine and resonant energy X-ray diffraction (REXD) to extract S. REXD is critical to distinguish between elements with similar Z-number (e.g. Zn and Ge). We found that samples with a corresponding to the ordered chalcopyrite structure had only partially ordered S values. The optical absorption onset for these films occurred at lower energy than expected for fully ordered ZnGeP₂, indicating that S is a more accurate descriptor of cation order than the stretching parameter. Since disorder is complex and can occur on many length scales, metrics for quantifying disorder should be chosen that most accurately reflect the physical properties of interest.

中文翻译：

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使用共振能量X射线衍射提取三元半导体中的化学有序参数

II–IV–V ₂材料，即III–V材料的三元类似物，因其在LED和太阳能电池等设备中的潜在应用而不断涌现。通过控制II–IV–V ₂材料中的阳离子有序性，可以在几乎固定的成分和晶格参数下调节性能。尽管通过排序以固定的晶格常数调整属性有可能成为设备制造中使用的强大工具，但阳离子排序也给排序的特征和量化带来了挑战。在这项工作中，我们研究了两种不同的方法来量化ZnGeP ₂薄膜中的阳离子有序性：从晶格常数计算出的拉伸参数和从阳离子位点占有率确定的有序参数（S）。我们使用高分辨率X射线衍射（HRXRD），以确定和共振能量X射线衍射（rexd会）提取小号。REXD对于区分具有相似Z值的元素（例如Zn和Ge）至关重要。我们发现具有与有序黄铜矿结构相对应的样品仅具有部分有序S值。这些薄膜的光吸收开始发生在比完全订购的ZnGeP ₂更低的能量上，表明S是比拉伸参数更准确的阳离子顺序描述符。由于疾病很复杂，并且可能在许多长度范围内发生，因此应选择最准确反映目标物理特性的量化疾病的指标。