Fabrication of the semiconductor superlattice by heteroepitaxy and its related evaluation

(1)在室温下，在InSb(111)A和InSb(111)B衬底上生长了α-锡薄膜，这两种衬底都有2×2的重构表面，这两种表面都是通过热清洗和离子外延生长的。用反射高能电子衍射和俄歇电子能谱研究了薄膜的表面相变。对于BOTIL系统，使用了两种类型的膜，每种膜具有不同厚度的8和30个单层[ML]，它们以逐层模式生长，以考察作为锡覆盖率的函数的膜的稳定性。在InSb(111)A上的α-Sn膜的情况下，8m1和30m1膜的表面都不可逆地经历了已知的3x3结构，通过2x2，随后经历了Werr的1x1结构。现在才发现，终于融化了。除熔融外，8毫升薄膜的转变温度比30毫升薄膜的转变温度高出十几度，30毫升薄膜从薄膜su…开始熔化。当温度为150ﾟC时，薄膜表面较宽，随后的熔化向薄膜衬底界面推进，而对于8ml薄膜，在220ﾟC时，整个薄膜迅速发生熔化。另一方面，对于α-锡/InSb(111)B薄膜，观察到Sb向锡膜的扩散。这与该系统的表面相变与α-Sn/InSb(111)A系统的表面相变有很大不同有关。最后，为了探讨α-锡在InSb(111)A上稳定的可能机制，我们进行了离散变分Xα团簇计算。(2)我们用Patterson函数、傅立叶分析和最小二乘修正确定了InSb(111)B-(2x2)重构表面的原子结构。提出的Sb三聚体模型充分解释了透射电子衍射和俄歇电子能谱的实验数据。新的结构是Sb三聚体的Sb-Sb键长为3.14A，位于衬底上方具有三重对称性的(2x2)结构的Sb原子。较少

(1) Thin films of alpha-Sn were grown of InSb(111)A and InSb(111)B substrates at room temperature, both having 2x2 reconstruction surfaces which were prepared by thermal cleaning and liomoepitaxial growth. Surface phase transition of the as-grown films was investigated by using reflection high energy electron diffraction and Auger electron spectroscopy. For botil systems, two types of the films, each having different thickness of 8 and 30 monolayers[ML], which grew with a layer-by-layer mode, were used to examine the stability of the films as a function of Sn coverage. In the case of the alpha-Sn film on InSb(111)A, the surfaces of both the 8ML and the 30ML films irreversibly underwent from the 3x3 structure as already known, via the 2x2 and subsequently the 1x1 structure which werr. nowly found, finally the melting. The transition temperature for the 8ML film were higher more than ten degrees than those for the 30ML except for the melting ; the 30ML film began to melt from the film su … More rface at 150ﾟC and the subsequent melting progressed toward the filmsubstrate interface, whereas for the 8ML film the melting promptly took place throughout the film at 220ﾟC. on the other hand, for alpha-Sn/InSb(111)B diffusion of Sb into the Sn film was observed. The behavior is related to the fact that the surface phase transition in this system is considerably different from that in the alpha-Sn/InSb(111)A system. Finally, in order to discuss possible mechanism for the stability of alpha-Sn on InSb(111)A, the discrete variational Xalpha cluster calculations were performed.(2) we have used Patterson function, Fourier analysis and least square refinement to determine atomic structures of the InSb(111)B-(2x2)reconstructed surface. The proposed Sb trimer model sufficiently explained the experimental data from transmission electron diffraction and Auger electron spectroscopy. The new structure is that an Sb trimer has the Sb-Sb bond length of 3.14 A and is located with three-fold symmetry above substrate Sb atoms consisting of the (2x2) structure. Less