Papers by Keyword: Ultra-Thin Film

Abstract: A Compact and precise gonio-stage for Grazing incidence X-ray absorption fine structure (GIXAFS) measurement is presented in this paper. The gonio-stage can provide a range of 0-35mrad and a resolution of 0.012mrad. An expert alignment can be realized automatically by computer program to obtain precise initial condition. An accuracy verification test of angle control carried out on BL7C station in KEK gives a satisfied result. At last, high quality GIXAFS spectra for 200nm thick HfO₂/Si thin film were obtained.

Abstract: Thin films and interfaces of crystalline organic dyes with semiconducting properties attracted a lot of attention in the last decade due to their numerous applications in electronics and optoelectronics. One of the most studied molecules is 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA); an archetypal organic material that can grow into multilayer films. Despite the great interest and intensive investigations, its optical properties are still not completely understood. The interpretations range from the Wannier-Mott exciton model to models of excitons of small radii. In the present work, we apply the Frenkel exciton model in order to describe the optical behavior of the solid phase of PTCDA, influenced by the transfer of excitations between different molecules. We are able to model the anisotropy of dielectric tensor, lineshape of the complex index of refraction, exciton dispersion and the large Stokes shift between absorption and photoluminescence, results of electron-energy loss spectroscopy, and photoluminescence transition energies and decay times. In addition, we made an extension of the model towards ultrathin PTCDA films.

Abstract: A novel micro-spray-assembly process and an automatic device to fabricate multilayer ultra-thin film are introduced. Employing self-assembly monolayer (SAM) technique, ultra-thin film can be assembled by utilizing the micro-spray-assembly device. The thickness and roughness of each monolayer can be controlled by varying various materials attributes, i.e., deposition time, ionic strength, pH value, molecular concentration and by selecting different manufacturing parameters of the automatic device such as spraying rate, size of micro-drop, N2 flow rate, temperature of N2 flow.

Abstract: Molecular dynamics simulation of nanoindentation on Al(111) surface is presented. The simulation is performed using the Ercolessi-Adams glue potential and the Berendsen thermostat. Boundary conditions of 'pseudo' thin film are imposed in order to focus on the dislocation motion in ultra-thin film. Nucleation and development of defects underneath the indenter tip are visualized, and the gliding patterns of dislocation loops are investigated with particular emphasis on the effect of film thickness. Simulation results show that the early emission of dislocation loop is highly dependent on the film thickness.