Atomic processes on ion-bombarded surface

1.用高能离子束轰击Al、Mo、Ti表面，分析了二次电子和离子能量随表面氧覆盖率的变化。并进行了详细的分析和讨论。用手工制作的半球分析仪对二次电子进行能量分析，该半球分析仪是相对于散射角的积分型。二次电子的产率和功函数的变化被测量为表面氧覆盖率的函数。用飞行时间型质量分析仪测量二次离子。结果表明，氧吸附引起的表面电子态的变化是这些二次粒子发射过程的基础。2.高电荷态离子的实验研究在掠入射条件下，高电荷态离子与固体表面的相互作用，以获得所谓的电势溅射细节。用飞行时间质量分析仪对从表面发射的二次离子与散射的中和射弹进行质量分析。用位置灵敏探测器和飞行时间分析仪测量了碎片离子的三维动量分布。研究了通过卤素传输原子层外延的方法制备的具有表面极性信息的x-GaN。发现（0001）面和（0001）面的质谱明显不同。吸附烃分子产生的H^+的动能分布在两个表面方向上也有很大差异。得出的结论是，表面极性可以有效地检查与本实验装置使用高电荷离子。

1.Experiment with high energy ion beamSecondary electrons and ions were energy analyzed as a function of surface-oxygen coverage under ion beam bombardment of Al, Mo, Ti surfaces. Basic analysis and discussions were made in detail. Secondary electrons were energy analyzed with a hand-made half sphere analyzer which is an integration type with respect to scattered angles. The yield of secondary electrons and change in the work function were measured as a function of surface-oxygen coverage. Secondary ions were measured with a time of flight type mass analyzer. It was found that the change of surface electronic state due to oxygen adsorption plays a fundamental role in emission processes of these secondary particles.2.Experiment with highly charged ionsInteraction between highly charged ions and solid surfaces were investigated under the condition of grazing incidence in order to pick up the detail of so called potential sputtering. Secondary ions emitted from a surface were mass analyzed with a time of flight mass analyzer in coincidence with scattered neutralized projectiles. The three dimensional momentum distribution of fragment ions was measured with a position sensitive detector coupled with a TOF analyzer. A cubic-GaN made by a method of halogen transport atomic layer epitaxy was investigated to have information on surface polarity. It was found that the mass spectra differ clearly between the (0001) and (0001) surfaces. The kinetic energy distribution of H^+ produced from adsorbed hydrocarbon molecules also widely differs for two surface directions. It was concluded that the surface polarity can be effectively checked with the present experimental setup using highly charged ions.