标题： 电子辐照对高温下单层MoS₂的影响 显示英文标题

标题： Electron-irradiation effects on monolayer MoS2 at elevated temperatures

摘要： 电子辐照对二维材料的影响是一个重要课题，既对于正确解释电子显微镜实验，也对于可能在电子光刻中的应用。 在最近表明了在描述束流损伤的理论模型中包括非弹性散射损伤的重要性，以及二维MoS2在电子辐照下缺乏氧气敏感性之后，温度的作用在定量层面仍未被探索。 在这里，我们展示了温度对单个缺陷的产生以及温度对缺陷动力学的影响。 基于通过原子分辨率扫描透射电子显微镜测量的MoS2中硫原子的位移截面，我们发现温度高达150{\deg }C时，缺陷产生的概率增加，这与理论预测一致。 然而，更高的温度会导致观察到的截面减少。 尽管有这种明显的减少，我们发现升高温度并没有减轻缺陷的产生，因为这一观察结果所暗示的相反情况，而是由于在检测之前创建的空位快速热扩散，从而隐藏了产生的损伤，导致在测量视野之外形成空位线和孔洞。 结合实验数据和先前报道的位移截面的理论模型，我们估计MoS2中硫空位的迁移能垒为0.26 +- 0.13 eV。 这些结果标志着向完全理解MoS2中电子束损伤迈出的又一步。 显示英文摘要

摘要： The effect of electron irradiation on 2D materials is an important topic, both for the correct interpretation of electron microscopy experiments and for possible applications in electron lithography. After the importance of including inelastic scattering damage in theoretical models describing beam damage, and the lack of oxygen-sensitivity under electron irradiation in 2D MoS2 were recently shown, the role of temperature has remained unexplored on a quantitative level. Here we show the effect of temperature on both the creation of individual defects as well as the effect of temperature on defect dynamics. Based on the measured displacement cross section of sulphur atoms in MoS2 by atomic resolution scanning transmission electron microscopy, we find an increased probability for defect creation for temperatures up to 150{\deg}C, in accordance with theoretical predictions. However, higher temperatures lead to a decrease of the observed cross sections. Despite this apparent decrease, we find that the elevated temperature does not mitigate the creation of defects as this observation would suggest, but rather hides the created damage due to rapid thermal diffusion of the created vacancies before their detection, leading to the formation of vacancy lines and pores outside the measurement's field of view. Using the experimental data in combination with previously reported theoretical models for the displacement cross section, we estimate the migration energy barrier of sulphur vacancies in MoS2 to be 0.26 +- 0.13 eV. These results mark another step towards the complete understanding of electron beam damage in MoS2.