NSRL在半导体表面结构的光电子衍射研究

Photoelectron diffraction studies on semiconductor surface structure in NSRL

利用角分辨光电发射精细结构(ARPEFS)技术研究了GaAs(001)面,验证了Biegelsen提出的钙双层模型的正确性。拟合结果显示,最外层构成二聚体的两个钙原子沿[110]方向移动聚拢,偏离体材料格位8.3%。同时最外层的钙原子向内收缩2.1%。利用X射线光电子衍射(XPD)实验技术研究了硫钝化方法处理过的GaAs(001)表面结构,确定了钝化的硫原子位于第一层钙原子的桥位上。与钙原子成键的键长为3.62?、键角为61.2°。使用与能量和角度有关的光电子衍射技术并结合多重散射团簇模型计算对Al2O3衬底上生长的GaN单晶薄膜表面的极化性质进行了研究,确定了该GaN表面极性为钙在最外层的正极化性。

The surface structure of GaAs(001) has been studied by using angle resolved photoemission fine structure (ARPEFS), which confirms the ‘Ga bi-layer’ model proposed by Biegelsen. The results show that two adjacent outmost Ga atoms (dimmer) move close together along [110] direction to form an 8.3% deviation from the bulk site. And the outmost Ga dimmers relax inward 2.1%. The surface structure of S-passivated GaAs(001) has also been investigated with the method of X-ray photoelectron diffraction (XPD). The results demonstrate that the passivated S atoms are located on the bridge of the first layer Ga atoms and bind them with the bond length of 3.62? and the bond angle of 61.2°. The surface polarity of GaN(0001) grown on the substrate of Al2O3 is also studied by using energy dependence photoelectron diffraction as well as the calculation of multiple scattering cluster models, which confirms that its polarity is Ga termination.