Fermi-level pinning can determine polarity in semiconductor nanorods
Fermi-level pinning can determine polarity in semiconductor nanorods
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DOI：
10.1103/physrevb.85.115404
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发表时间：
2011-10
影响因子：
3.7
通讯作者：
P. Avraam;N. Hine;Paul Tangney;P. Haynes
中科院分区：
文献类型：
--
作者：
P. Avraam;N. Hine;Paul Tangney;P. Haynes
极性半导体纳米棒的第一性原理计算表明，它们的偶极矩受到费米能级钉扎的强烈影响。孤立的纳米棒的费米能级被发现与在端面处的电子表面态的显著密度相一致，所述电子表面态是中间带隙态或带边态。这些状态钉扎费米能级，因此固定了杆两端的电势差。我们提供的证据表明，这种效应可以对纳米棒的极性产生决定性的影响，其结果是棒响应其表面化学变化的方式，其偶极矩随其大小的缩放，以及极性对其组成的依赖性。
First-principles calculations of polar semiconductor nanorods reveal that their dipole moments are strongly influenced by Fermi-level pinning. The Fermi level for an isolated nanorod is found to coincide with a significant density of electronic surface states at the end surfaces, which are either mid-gap states or band-edge states. These states pin the Fermi level, and therefore fix the potential difference across the rod. We provide evidence that this effect can have a determining influence on the polarity of nanorods, with consequences for the way a rod responds to changes in its surface chemistry, the scaling of its dipole moment with its size, and the dependence of polarity on its composition.