Design and melt growth for novel photonic crystals by micro pulling down method

点击翻译按钮获取中文摘要

In the present study, our research topic is photonic crystal for optical innovation. In order to realize a development of bulk materials based on novel properties of photonic crystal by nanotechnology, we performed establishment of materials design by computer simulation, high speed melt growth by micro pulling down method and evaluation scheme for photonic band gap based on the calculation results.The Marangoni convection that appeared under the microgravity condition was taken into account to computational fluid dynamics calculation code (finite volume method) for a conventional Czochralski method and the micro pulling down method, and a high accuracy simulation technique was established. We proposed Adjustable Rotating Ring Czochralski method(ARRCZ) that is a new convection control method for a large diameter high-quality single crystal, the stability of the growth speed of the seed crystal by this control method, the smoothness of the interface of solid and liquid phases, and convection were examined, and these results reveal for the best single crystal growth condition in this year.Eutectic materials were grown by the micro pulling down method. Stoichiometric mixture of 4N powder such as Al_2O_3 and Y_2O_3 were used as starting materials and preliminary sintered. The growth was carried with Ir crucible under inert atmosphere using seed crystals. This year several eutectic materials such as Al_2O_3/Y_3Al_5O_<12>, Al_2O_3/Y_3Al_5O_<12>/ZrO_2 and MgAl_2O_4/MgO have grown and properties were investigated. As a result, factors to influence micro structure were clarified. Material systems, impurities and growth speed were especially effective factors. In MgAl_2O_4/MgO system, regular pattern of MgO in the matrix was observed and MgO part was selectively etched by acid.