Study of Crystal Surfaces by Ion Surface Blocking

为了研究晶体表面，研究了表面原子平面对表面原子散射离子的阻塞效应(表面阻塞)。在超高压条件下，观察到1 MeV He离子入射到SnTe晶体(001)原子清洁表面的表面阻挡离子的能量损失。观察到的能量损失依赖于相对于表面的激发角。提出了一种利用表面阻挡来确定表面附近位置相关阻挡能力的新方法，并设计了一台用于表面阻挡测量的90ﾟ倾斜边界双向聚焦扇形磁谱仪。利用该光谱仪可以从单晶表面散射离子的能谱中分辨出连续原子层的散射离子，并利用MeV光离子在晶体表面的掠射角散射研究了外延生长的初期阶段。结果表明，在SNTE(001)衬底上外延生长碳化铅时，由于失配位错的形成，表面发生了变形。

The blocking effect at surface atomic planes on ions scattered from surface atoms (surface blocking) was investigated in order to study crystal surfaces. Energy losses of the surface blocking ions were observed for 1 MeV He+ ions incident on an atomically clean (001) surface of a SnTe crystal under UHV conditions. The observed energy loss depends on the excite angle relative to the surface plane. A new method was proposed to determine the position dependent stopping power near the surface using surface blocking.A 90ﾟ sector magnetic spectrometer with inclined boundaries for two-directional focusing was designed for the surface blocking measurement. Using this spectrometer, ions scattered from successive atomic layers could be resolved in the energy spectra of the scattered ions from single crystal surfaces.Initial stage of epitaxial growth was investigated using glancing angle scattering of MeV light ions on crystal surfaces. It was shown that the surface is distorted during the epitaxial growth of Lead Charcogenides on SnTe(001) due to the formation of misfit dislocations.