Epitaxial Growth of Non-Equilibrium Crystals and their Exciton Spectra

1.为非平衡离子晶体的外延生长搭建了一个新的真空室。以真空解理的RbBr(100)晶面为衬底，成功地在其上生长了氯化钠结构的CsI薄膜。在真空解理的RBI单晶上制备了Csci结构的CsI薄膜。两种薄膜的厚度都在5 nm左右。在吸收光谱中，两种薄膜均显示出明显的氯化钠和氯化铯激子带。研究了一些样品的发光特性，特别是在本Grant-in-Aid购买的Nd：YAG激光器的激发下的衰变曲线。PbF_2晶体即使在正常条件下也有两种不同的结构变化：立方结构和正交结构。研究了这两种物相的几种光谱。所取得的部分成果已发表或接受出版。

1. A new vacuum chamber was constructed for epitaxial growth of non-equilibrium ionic crystals.2. By using a RbBr (100) crystal surface cleaved in vacuum as a substrate, NaCl-structured CsI thin films were successfully grown on it.3. CsCI-structured CsI thin films were also prepared on a RbI single crystal cleaved in vacuum.4. The thickness of both films was about 5 nm.5. Both films were found to show sharp exciton bands of NaCl- and CsCl-types in the absorption spectra, respectively.6. Luminescence properties, especially decay profile, of some samples were investigated under the excitation with a Nd : YAG laser purchased by the present Grant-in-Aid.7. The PbF_2 crystal has two different structural modifications even at normal condition ; cubic and orthorhombic. Several kinds of optical spectra of both phases were studied. A part of the obtained results have been already published or accepted for publication.