Yang Leilei, Chen Wenjun, Yang Rongliang, Chen Anqi, Zhang Hao, Sun Yibo, Jia Yufei, Li Xinming, Tang Zikang, Gui Xuchun
State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China.
College of Innovation and Entrepreneurship, Southern University of Science and Technology, Shenzhen 518055, China.
ACS Appl Mater Interfaces. 2020 Mar 4;12(9):10755-10762. doi: 10.1021/acsami.9b18650. Epub 2020 Feb 19.
Two-dimensional (2D) MoC, as a new member of transition metal carbides, has many intriguing properties and potential applications in superconductors and electronic devices. The thermal stability of 2D materials is essential for the performance of the related devices, especially the ones with a vertical heterostructure. However, rare reports have demonstrated the thermal stability of MoC and the effects of thermal stability on its performance. Here, we propose a facile and controllable method to directly oxidize MoC to MoO, forming a MoO/MoC heterostructure. During the oxidization process, an in situ technique is employed to uncover the transformation and thermal stability of the MoC. The chemical vapor deposition MoC shows high structural stability below 550 °C in Ar or below 350 °C in O, which demonstrates the high thermal stability and antioxidation of the MoC film. The metallic MoC is gradually oxidized to semiconducting MoO as the temperature increases above 350 °C. The oxidization rate can be easily controlled by adjusting the oxidation temperature and time. Further, the obtained MoO/MoC vertical hybrid structure shows obvious Schottky junction behaviors, strongly indicating the perfect interfacial contact between the component layers. This work offers a new strategy for the controllable fabrication of high-quality 2D heterostructures.
二维（2D）碳化钼（MoC）作为过渡金属碳化物的新成员，在超导体和电子器件中具有许多引人入胜的特性和潜在应用。二维材料的热稳定性对于相关器件的性能至关重要，尤其是对于具有垂直异质结构的器件。然而，关于MoC热稳定性及其对性能影响的报道很少。在此，我们提出了一种简便可控的方法，将MoC直接氧化为MoO，形成MoO/MoC异质结构。在氧化过程中，采用原位技术揭示MoC的转变和热稳定性。化学气相沉积的MoC在Ar气氛中550℃以下或O气氛中350℃以下表现出高结构稳定性，这表明MoC薄膜具有高热稳定性和抗氧化性。随着温度升高到350℃以上，金属态的MoC逐渐氧化为半导体态的MoO。通过调节氧化温度和时间可以轻松控制氧化速率。此外，所获得的MoO/MoC垂直混合结构表现出明显的肖特基结行为，有力地表明了组成层之间完美的界面接触。这项工作为高质量二维异质结构的可控制备提供了一种新策略。
