Air Passivation of Chalcogen Vacancies in Two-Dimensional Semiconductors
Air Passivation of Chalcogen Vacancies in Two-Dimensional Semiconductors
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DOI：
10.1002/anie.201508828
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发表时间：
2016-01-18
影响因子：
16.6
通讯作者：
Wei, Su-Huai
中科院分区：
文献类型：
--
作者：
Liu, Yuanyue;Stradins, Pauls;Wei, Su-Huai
缺陷在半导体(SC)中起着重要作用。与块状SCs不同，二维(2D)SCs中的缺陷暴露在周围环境中，这可能会改变其属性/功能。空气是一种常见的环境，但它对二维SCS中缺陷的影响仍然难以捉摸。在这里，我们研究了空气和硫族空位(V-X)之间的相互作用，这是2D SCS中最典型的缺陷。虽然大多数分子在空气中的相互作用很弱，但氧-2可以通过与SC结合能相关的势垒在V-X处化学吸附，并且即使在室温下对某些SC也可以克服。重要的是，化学吸附的O-2将V-X从通常认为有害的载流子陷阱改变为电子上的良性位置。这种不寻常的行为源于O-2和X在与金属结合时的等价态。在此基础上，提出了一种利用空气/氧气钝化缺陷来改善二维SCS性能的简便方法。
Defects play important roles in semiconductors (SCs). Unlike those in bulk SCs, defects in two-dimensional (2D) SCs are exposed to the surrounding environment, which can potentially modify their properties/functions. Air is a common environment, yet its impact on the defects in 2D SCs still remains elusive. Here we study the interaction between air and chalcogen vacancies (V-X), the most typical defects in 2D SCs. Although the interaction is weak for most molecules in air, O-2 can be chemisorbed at V-X with a barrier that correlates with the SC cohesive energy and can be overcome even at room temperature for certain SCs. Importantly, the chemisorbed O-2 changes the V-X from commonly believed harmful carrier-traps to electronically benign sites. This unusual behavior originates from the isovalence between O-2 and X when bonded with metal. Based on these findings, a facile approach is proposed to improve the performance of 2D SCs by using air/O-2 to passivate the defects.