Universal alignment of surface and bulk oxygen levels in semiconductors
Universal alignment of surface and bulk oxygen levels in semiconductors
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DOI：
10.1063/5.0052521
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发表时间：
2021-07
影响因子：
4
通讯作者：
V. Chakrapani
中科院分区：
文献类型：
--
作者：
V. Chakrapani
氧和氢是半导体中最重要的两种杂质，因为它们在生长和器件加工环境中无处不在，因此，它们的掺入强烈影响电子和电学性质。因此，更深入地了解这些物种与半导体表面和体缺陷的相互作用对于开发基于它们的设备，如光伏和光催化系统以及燃料电池是必要的。通过对所报道的表面功函数值和替代体O-缺陷能量的分析，这里表明，具有物理吸附的O2的半导体的表面费米能级普遍位于真空能级以下约-5.1 eV。类似地，结果表明，在晶体生长过程中引入的替代体O相关两性缺陷的能量也具有相对于大多数研究的半导体真空能级的通用能量为1.5 - 5.0 eV。它表明，“表面转移掺杂”的过程中，涉及在半导体表面上的吸附水膜可能是负责的氧水平的普遍排列。
Oxygen and hydrogen are the two most important impurities in semiconductors because of their ubiquitous presence in growth and device processing environments, and consequently, their incorporation strongly influences electronic and electrical properties. Therefore, a deeper understanding of the interaction of these species with the semiconductor surface and bulk defects is necessary for enabling the development of devices based on them, such as photovoltaic and photocatalytic systems and fuel cells. It is shown here, through the analysis of the reported surface work function values and substitutional bulk O-defect energies, that the surface Fermi level of semiconductors with physisorbed O2 lies universally at approximately −5.1 eV below the vacuum level. Similarly, the results show that the energy of substitutional bulk O-related amphoteric defects incorporated during the crystal growth also has a universal energy of ∼−5.0 eV with respect to the vacuum level for most semiconductors investigated. It is shown that the process of “surface transfer doping” involving an adsorbed water film on the semiconductor surface is likely responsible for the universal alignment of oxygen levels.