Dynamics of the low-energy ion impact on the vander Warls thin films

低能离子与固体表面相互作用的研究在等离子体技术和离子束技术领域具有重要的基础意义。本文详细研究了低能离子对范德华薄膜的冲击动力学。新设计的反射式TOF质谱仪安装在超高真空室中。在7 K温度下，将脉冲离子束注入沉积在冷冻机冷头上的范德华薄膜中。当薄膜被He^+离子轰击时，几乎观察不到团簇离子。相反，碎片离子形成具有很强的强度。这是由于在离子-固体碰撞事件中，小尺寸He^+离子的动能主要由电子激发耗散。相比之下，在Ne^+与固体薄膜的碰撞中发生了更有效的动量转移。碰撞过程中有效的动量传递导致离子轨道中激波的形成。这导致了大量的簇离子形成。综上所述，在基体中形成的空穴和激子在二次离子形成中起着非常重要的作用。

The study on the interactions between the low-energy ions and solid surface is of fundamental importance in the field of plasma technology and ion-beam technology. In this study, the dynamics of the low-energy ion impact on the van der Waals thin films were studied in detail. The newly designed reflectron-type TOF mass spectrometer was installed in the ultra-high vacuum chamber. The pulsed ion beam was injected into the van der Waals thin film deposited on the cold head of the cryocooler at 7 K.When the film was bombarded by the He^+ ions, the cluster ions were hardly observed. Instead, fragment ions are formed with strong intensities. This is due to the fact that the kinetic energy of the small-size He^+ ion is mainly dissipated by the electronic excitation in the ion-solid collision events. In contrast, much more efficient momentum transfer takes place in the collision of Ne^+ with the solid films. The efficient momentum transfer in the collision events leads to the shock wave formation in the ion track. This results in the abundant cluster ion formation.In sum, the holes and excitons formed in the matrix play very important roles in the secondary ion formatin.