Interfacial Interaction between HfO2 and MoS2: From Thin Films to Monolayer

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• 作者：Ming Yang ; Jian Wei Chai ; Martin Callsen ; Jun Zhou ; Tong Yang ; Ting Ting Song ; Ji Sheng Pan ; Dong Zhi Chi ; Yuan Ping Feng ; Shi Jie Wang
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：May 12, 2016
• 年：2016
• 卷：120
• 期：18
• 页码：9804-9810
• 全文大小：475K
• 年卷期：0
• ISSN：1932-7455

文摘

The interfacial interaction between high-κ dielectrics and two-dimensional channel materials plays an important role in determining electronic properties of high-performance electronic devices. In this study, via first-principles calculations, we show that the interaction between oxygen-terminated HfO₂ (111) and the MoS₂ monolayer is weak and dominated by the van der Waals force. This weak interaction results in symmetric band offsets which are larger than 1 eV. The presence of oxygen vacancies in HfO₂ enhances the interfacial interaction significantly, leading to electron–hole puddles, larger effective masses, and localized midgap states in the MoS₂. In contrast, strong interaction is found at the interface of hafnium-terminated HfO₂ (111) and the MoS₂ monolayer, but it results in inferior electronic properties. In addition, when the thickness of MoS₂ increases, the formation of an oxygen-terminated HfO₂ thin film on MoS₂ becomes endothermic accompanied by asymmetrically increased band offsets due to reduced band gaps of MoS₂ thin films. Our results reveal surface- and thickness-dependent interfacial interaction between a high-κ dielectric and a two-dimensional material and might shed light on the integration of high-κ dielectrics into two-dimensional materials based electronic devices.