论文标题
cu $ _ {3-x} $ p是半导体，金属还是半学？
Is Cu$_{3-x}$P a semiconductor, a metal, or a semimetal?
论文作者
论文摘要
尽管最近对Cu $ _ {3-X} $ P的兴趣激增，用于催化，电池和等离子体，但Cu $ _ {3-X} $ P的电子性质仍不清楚。一些研究表明了半导体行为的证据，而其他研究则认为Cu $ _ {3-X} $ P是金属化合物。在这里，我们试图基于组合薄膜实验，电子结构计算和半经典鲍尔茨曼运输理论来解决这一难题。我们发现有力的证据表明，化学计量，无缺陷的Cu $ _3 $ P是一种内在的半学，即价值和传导带之间的重叠较小的材料。另一方面，实验可实现的cu $ _ {3-x} $ p胶片始终是p型半光，无论$ x $何种，铜空缺都在铜空位上掺杂。 Cu $ _ {3-X} $ P样品具有很小的特征大小（例如小纳米颗粒）是半导体，这并不令人难以置信，这是由于量子限制效应而导致频带间隙打开的量子限制效应。我们在低温下观察到Cu $ _ {3-X} $ P膜中的高孔迁移率（276厘米$^2 $/vs），尽管掺杂密度很高，但仍指向低电离杂质散射率。我们报告了相当于爆发素偏移的光学效应，并将红外吸收峰分配给了散装的频带间跃迁，而不是表面等离子体的共振。从材料处理的角度来看，这项研究证明了反应性溅射沉积的适用性，可详细介绍新兴金属磷化物的高通量研究。
Despite the recent surge in interest in Cu$_{3-x}$P for catalysis, batteries, and plasmonics, the electronic nature of Cu$_{3-x}$P remains unclear. Some studies have shown evidence of semiconducting behavior, whereas others have argued that Cu$_{3-x}$P is a metallic compound. Here, we attempt to resolve this dilemma on the basis of combinatorial thin-film experiments, electronic structure calculations, and semiclassical Boltzmann transport theory. We find strong evidence that stoichiometric, defect-free Cu$_3$P is an intrinsic semimetal, i.e., a material with a small overlap between the valence and the conduction band. On the other hand, experimentally realizable Cu$_{3-x}$P films are always p-type semimetals natively doped by copper vacancies regardless of $x$. It is not implausible that Cu$_{3-x}$P samples with very small characteristic sizes (such as small nanoparticles) are semiconductors due to quantum confinement effects that result in opening of a band gap. We observe high hole mobilities (276 cm$^2$/Vs) in Cu$_{3-x}$P films at low temperatures, pointing to low ionized impurity scattering rates in spite of a high doping density. We report an optical effect equivalent to the Burstein-Moss shift, and we assign an infrared absorption peak to bulk interband transitions rather than to a surface plasmon resonance. From a materials processing perspective, this study demonstrates the suitability of reactive sputter deposition for detailed high-throughput studies of emerging metal phosphides.
