Layer-by-Layer Oxidation Induced Electronic Properties in Transition-Metal Dichalcogenides
Layer-by-Layer Oxidation Induced Electronic Properties in Transition-Metal Dichalcogenides
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DOI：
10.1021/acs.jpcc.8b05857
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发表时间：
2018-07-26
影响因子：
3.7
通讯作者：
Dutta, Sudipta
中科院分区：
文献类型：
--
作者：
Das, Soumya Ranjan;Wakabayashi, Katsunori;Dutta, Sudipta
过渡金属二硫化物的最新进展为基于原子级薄纳米材料的电子器件应用开辟了新的可能性。在此，我们在第一性原理框架内研究了在单层和少层二硫化物体系中通过逐层控制氧化调制的原子级自组装异质结及其电子特性。原始的二硫化物体系呈现半导体行为。我们观察到顶层部分氧化时带隙减小。然而，如近期实验所观察到的，由于电荷从原始层转移到氧化层，顶层完全氧化会使体系呈金属性。当底层部分氧化且顶层完全氧化时，体系呈现出前所未有的半金属行为。价带极大值和导带极小值出现在不同的k点会引入能谷极化。因此，我们的研究表明，在基于二硫化物的异质结中，可控氧化诱导了不同的电子特性，可用于先进的电子、光电子和能谷电子器件应用。
Recent progress in transition-metal dichalcogenides has opened up new possibilities for atomically thin nanomaterial based electronic device applications. Here we investigate atomic-scale self-assembled heterojunction modulated by layer-by-layer controlled oxidation in monolayer and few-layer dichalcogenide systems and their electronic properties within a first-principles framework. Pristine dichalcogenide systems exhibit semiconducting behavior. We observe reduction of the band gap for partial oxidation of the top layer. However, complete oxidation of the top layer makes the system metallic, owing to the charge transfer from the pristine to the oxidized layer, as observed in recent experiments. When the bottom layer gets partially oxidized with fully oxidized top layers, the system shows unprecedented semimetallic behavior. The appearance of valence band maximum and conduction band minimum at different k-points can introduce valley polarization. Therefore, our study shows controlled oxidation induced varying electronic properties in dichalcogenide based heterojunctions that can be exploited for advanced electronic, optoelectronic, and valleytronic device applications.