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arXiv · 1511.07898

Air passivation of chalcogen vacancies in two-dimensional semiconductors

Yuanyue Liu·Pauls Stradins·Su-Huai Wei
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Abstract

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. In this work, we unravel the interaction between air and chalcogen vacancies (VX)-the most typical defects in 2D SCs. We find that, although the interaction is weak for most molecules in air, O2 can be chemisorbed at VX with a barrier that correlates with the SC cohesive energy and can be overcame even at room temperature for certain SCs. Importantly, the chemisorbed O2 changes the VX from commonly-believed harmful carrier-traps to electronically benign sites. This unusual behavior originates from the iso-valence between O2 and X when bonded with metal. Based on these findings, we propose a facile approach to improve the performance of 2D SCs by using air to passivate the defects.

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Yuanyue Liu, Pauls Stradins, Su-Huai Wei. 2015-11-24. Air passivation of chalcogen vacancies in two-dimensional semiconductors. https://doi.org/10.1002/anie.201508828

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