Impact of vacancies on electronic properties of black phosphorus probed by STM
Impact of vacancies on electronic properties of black phosphorus probed by STM
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DOI：
10.1063/1.5016988
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发表时间：
2018-01
影响因子：
3.2
通讯作者：
J. Riffle;C. Flynn;B. S. Laurent;C. Ayotte;C. Caputo;S. Hollen
中科院分区：
文献类型：
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作者：
J. Riffle;C. Flynn;B. S. Laurent;C. Ayotte;C. Caputo;S. Hollen
黑磷(BP)因其直接0.4-1.5 eV的层相关带隙和高迁移率而受到人们的广泛关注。由于BP设备依赖于块状晶体的剥离，因此有必要了解来源材料中的天然杂质和缺陷。特别是，样品通常是p掺杂的，但掺杂的来源还不清楚。在这里，我们使用扫描隧道显微镜和光谱学来比较来自两个商业来源的BP样品的原子缺陷。尽管两个源产生的晶体中的杂质原子相差一个数量级，但我们观察到了类似的缺陷密度和p掺杂水平。我们将这些缺陷归因于P空位，并提供了它们是P掺杂的来源的证据。我们还将这些本征缺陷与空气暴露引起的缺陷进行了比较，结果表明它们是不同的，并且可能对电子结构的控制更为重要。这些结果表明，与商业材料中普遍存在的空位相比，BP中的杂质所起的作用较小，因此需要更好地控制空位缺陷。黑磷(BP)因其直接的0.4-1.5 eV层相关带隙和高迁移率而受到广泛关注。由于BP设备依赖于块状晶体的剥离，因此有必要了解来源材料中的天然杂质和缺陷。特别是，样品通常是p掺杂的，但掺杂的来源还不清楚。在这里，我们使用扫描隧道显微镜和光谱学来比较来自两个商业来源的BP样品的原子缺陷。尽管两个源产生的晶体中的杂质原子相差一个数量级，但我们观察到了类似的缺陷密度和p掺杂水平。我们将这些缺陷归因于P空位，并提供了它们是P掺杂的来源的证据。我们还将这些本征缺陷与空气暴露引起的缺陷进行了比较，结果表明它们是不同的，并且可能对电子结构的控制更为重要。这些结果表明，与石油天然气相比，BP中的杂质所起的作用较小。
Black phosphorus (BP) is receiving significant attention because of its direct 0.4–1.5 eV layer-dependent bandgap and high mobility. Because BP devices rely on exfoliation from bulk crystals, there is a need to understand the native impurities and defects in the source material. In particular, samples are typically p-doped, but the source of the doping is not well understood. Here, we use scanning tunneling microscopy and spectroscopy to compare the atomic defects of BP samples from two commercial sources. Even though the sources produced crystals with an order of magnitude difference in impurity atoms, we observed a similar defect density and level of p-doping. We attribute these defects to phosphorus vacancies and provide evidence that they are the source of p-doping. We also compare these native defects to those induced by air exposure and show that they are distinct and likely more important for the control of electronic structure. These results indicate that impurities in BP play a minor role compared to vacancies, which are prevalent in commercially available materials, and call for better control of vacancy defects.Black phosphorus (BP) is receiving significant attention because of its direct 0.4–1.5 eV layer-dependent bandgap and high mobility. Because BP devices rely on exfoliation from bulk crystals, there is a need to understand the native impurities and defects in the source material. In particular, samples are typically p-doped, but the source of the doping is not well understood. Here, we use scanning tunneling microscopy and spectroscopy to compare the atomic defects of BP samples from two commercial sources. Even though the sources produced crystals with an order of magnitude difference in impurity atoms, we observed a similar defect density and level of p-doping. We attribute these defects to phosphorus vacancies and provide evidence that they are the source of p-doping. We also compare these native defects to those induced by air exposure and show that they are distinct and likely more important for the control of electronic structure. These results indicate that impurities in BP play a minor role compare...