SnSe,一种环境友好的IV族单硫系半导体,在从热电设备到太阳能收集的各种应用中表现出卓越的性能。其超薄薄膜在铁电非易失性器件的制造中显示出希望。然而,超薄SnSe单晶薄膜中点缺陷的微观识别和操纵,这显著影响了它们的电子结构,没有得到充分的研究。这项研究提供了通过分子束外延生长的单层SnSe薄膜中点缺陷的全面研究。通过将扫描隧道显微镜(STM)表征与第一性原理计算相结合,我们确定了四种类型的原子/分子空位,四种类型的原子替换,和三种类型的外在缺陷。值得注意的是,我们已经证明了通过使用STM尖端操纵单个原子或分子将替代缺陷转化为空位并重新定位被吸附物的能力。我们还分析了空位引起的局部原子位移。这项工作为未来SnSe基纳米器件的电子结构工程提供了坚实的基础。
SnSe, an environmental-friendly group-IV monochalcogenide semiconductor, demonstrates outstanding performance in various applications ranging from thermoelectric devices to solar energy harvesting. Its ultrathin films show promise in the fabrication of ferroelectric nonvolatile devices. However, the microscopic identification and manipulation of point defects in ultrathin SnSe single crystalline films, which significantly impact their electronic structure, have been inadequately studied. This study presents a comprehensive investigation of point defects in monolayer SnSe films grown via molecular beam epitaxy. By combining scanning tunneling microscopy (STM) characterization with first-principles calculations, we identified four types of atomic/molecular vacancies, four types of atomic substitutions, and three types of extrinsic defects. Notably, we have demonstrated the ability to convert a substitutional defect into a vacancy and to reposition an adsorbate by manipulating a single atom or molecule using an STM tip. We have also analyzed the local atomic displacement induced by the vacancies. This work provides a solid foundation for engineering the electronic structure of future SnSe-based nanodevices.