论文标题
通过电子辐射在超低加速电压下通过电子辐照在单层MOS2中受控的缺陷产生
Controlled defect production in monolayer MoS2 via electron irradiation at ultralow accelerating voltages
论文作者
论文摘要
使用电子束照射可以控制2D材料中缺陷的空间位置和密度。相反，超动加速电压（小于或等于5kV）用于测量表面形态，而没有预期的缺陷产生。我们发现在这些电压下单层（ML）MOS2中缺陷创造的明确特征。 E'和a1'拉曼模式的演变，具有电子剂量，而缺陷激活峰的出现表示缺陷形成。为了模拟MOS2的拉曼在现实缺陷分布中的拉曼光谱，同时保持密度功能理论的准确性，我们结合了声子的机器学习力场和拉曼张量的特征模式投影方法。模拟光谱与实验一致，硫空位如建议的缺陷。我们使用对照（HBN覆盖和封装的MOS2）样品解除了缺陷，掺杂和碳质污染。我们观察到低温PL淬灭和缺陷峰，发现碳污染不会影响缺陷。这些研究在光子学和量子发射器中有应用。
Control on spatial location and density of defects in 2D materials can be achieved using electron beam irradiation. Conversely, ultralow accelerating voltages (less than or equal to 5kV) are used to measure surface morphology, with no expected defect creation. We find clear signatures of defect creation in monolayer (ML) MoS2 at these voltages. Evolution of E' and A1' Raman modes with electron dose, and appearance of defect activated peaks indicate defect formation. To simulate Raman spectra of MoS2 at realistic defect distributions, while retaining density-functional theory accuracy, we combine machine-learning force fields for phonons and eigenmode projection approach for Raman tensors. Simulated spectra agree with experiments, with sulphur vacancies as suggested defects. We decouple defects, doping and carbonaceous contamination using control (hBN covered and encapsulated MoS2) samples. We observe cryogenic PL quenching and defect peaks, and find that carbonaceous contamination does not affect defect creation. These studies have applications in photonics and quantum emitters.
