MECHANISMS OF EPITAXY AND PROPERTIES OF COHERENT THIN FILMS

1)REM研究揭示了Au在Si（111）邻位上吸附引起的结构相变和吸附原子密度的变化，并在Si（111）邻位上形成小面; 2）对[110]区小面研究的扩展，发现了不同的小面及其粗糙化相变和它们的覆盖度依赖性; 3）SPA-LEED和REM研究了Au在Si（001）邻位上的吸附.结果表明，Au的吸附可以使Si（111）表面吸附原子的有效电荷从正电荷反转为负电荷。5）在Si（111）表面上沉积少量的Ag、Au和Cu<21><21>，通常可以观察到ROO <3>x ROO<3>结构。6）在Si（111）ROO x ROO Ag的情况下，首次在4K下用STM观察到半导体表面的驻波<3><3>。7）发现Pb吸附在Si（111）表面形成的绝缘吸附物结构在200 K时转变为7 x ROO结构<3>。表面在230 ℃左右在c2 x8和无序1x 1结构之间有可逆的结构相变。C60分子在金属吸附的Si表面上表现出依赖于金属诱导的超晶格的外延关系。11）在4K下测量Ag/Si（111）体系的电导率，发现在2 mnolayr能级上存在金属-绝缘体转变。

1) REM study revealed successive Au adsorption induced structural phase transitions and adatom densities in the 1 x 1 pahse and facet formation on vicinal Si (111) surfaces.2) Extensoion of above work fo the studies of facetting on [110] zone found various facet planes and their roughening phase transitions and their coverage dependences.3) SPA-LEED and REM studies of Au adsorbed vicinal (001) surface were carried out as a cooperative research works and they revealed dynamics of facet formation4) We revealed that effective charge of adatom Si on Si (111) surface can be reversed from positive to negative by adosrption of Au5) ROO<21>x ROO<21> structures were commonly observed on Si (111) ROO<3>x ROO<3>Ag by deposition of small amounts of Ag, Au and Cu.6) Standing waves on semiconductor surfaces were firstly observed by STM in case of Si (111) ROO<3>x ROO<3>Ag at 4K.7) It was found that an incommensulate adsorbate structure formed by Pb adsroption on Si (111) transforms to 200K to a 7x ROO<3> structure.8) Adatoms on quenched clean Si (111) surfaces have a reversible structural phase transition at around 230ﾟC between the c2x8 and disordered 1x1 strcutures.9) C60 molecules showed epitaxial relations on metal adsorbed Si surfaces depending on the superlattices induced by metals.10) Systematic studies were carried out by SPA-LEED for studies of formation of various types of defects in cases of various adsorption systems and epitaxy of CaF_2 were studied.11) From a conductivity measurements at 4k for systems of Ag/Si (111) a metal-insulator transition at 2 mnolayr level was observed.