Self-Limiting Layer-by-Layer Oxidation of Atomically Thin WSe2
Self-Limiting Layer-by-Layer Oxidation of Atomically Thin WSe2
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DOI：
10.1021/nl5049753
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发表时间：
2015-03-01
期刊：
影响因子：
10.8
通讯作者：
Tsukagoshi, Kazuhito
中科院分区：
文献类型：
--
作者：
Yamamoto, Mahito;Dutta, Sudipta;Tsukagoshi, Kazuhito
在二维过渡金属二硫属化合物上生长厚度可调的均匀氧化物薄膜对于电子学和光电应用具有重要意义。在这里，我们展示了均匀的表面氧化的原子级薄的WSe 2与自限厚度从单到三层。暴露于低于100摄氏度的臭氧（O-3）导致氧化钨选择性地沿沿着硒的边缘取向在WSe 2上横向生长。随着进一步的O-3暴露，氧化物区域聚结并且氧化终止，在未氧化的WSe 2的顶部上留下均匀厚度的氧化物膜。在较高温度下，氧化以逐层方式发展到三层。在WSe 2上形成的氧化膜几乎是原子级平坦的。使用光致发光和拉曼光谱，我们发现，底层的单层WSe 2是去耦的顶部氧化物，但空穴掺杂。我们的研究结果提供了一个新的策略，创造原子级薄的异质结构的半导体和绝缘氧化物在电子器件中的应用潜力。
Growth of a uniform oxide film with a tunable thickness on two-dimensional transition Metal dichalcogenides is of great importance for electronic and optoelectronic applications. Here we demonstrate homogeneous surface oxidation of atomically thin WSe2 with a self-limiting thickness from single- to trilayers. Exposure to ozone (O-3) below 100 degrees C leads to the lateral growth of tungsten oxide selectively along selenium zigzag-edge orientations on WSe2. With further O-3 exposure, the oxide regions coalesce and oxidation terminates leaving a uniform thickness oxide film on top of unoxidized WSe2. At higher temperatures, oxidation evolves in the layer-by-layer regime up to trilayers. The oxide films formed on WSe2 are nearly atomically flat. Using photoluminescence and Raman spectroscopy, we find that the underlying single-layer WSe2 is decoupled from the top oxide but hole-doped. Our findings offer a new strategy for creating atomically thin heterostructures of semiconductors and insulating oxides with potential for applications in electronic devices.