Silicon solar cells with high efficiency based on control of light elements in the crystals
Effective control of carbon concentration in a crystal is required for the production of a high-quality crystal. We proposed an improved unidirectional solidification furnace to produce crystals with lower carbon concentration. The global simulation of coupled oxygen and carbon transports within this furnace was used to validate the feasibility of its improved design.
Workshop on 3D atomic imaging techniques
奈良先端大学大学院物質創成科学研究科 大門 寛
We held the workshop on the 3D imaging of atoms, based on holography and phase retrieval methods of X-ray, electron and neutron scatterings. Topics on electron and X-ray emission holography, surface (interface) scattering holography, and coherent electron and X-ray diffractive imaging methods were intensively discussed during the workshop. Toward examining middle range local structures of materials contributable to green and life sciences, we set a new goal for the improvements of these methods.
Computational Approach to Properties of Thermoelectric and Other Materials
山口大学大学院理工学研究科 嶋村 修二
The effect of defects on the electronic structures of type-VIII Ba8Ga16Sn30 (BGS) clathrates, promising thermoelectric materials, has been investigated by ab initio electronic structure calculations. The solid and dotted curves denote the band structures near the band gap of BGS with and without defects, respectively. The defects change notably the valence bands, but little the conduction bands. This is in good agreement with experimental results of carrier properties of BGS.
Low energy magnetic excitations in the iron-based superconductor Fe(Se1-xTex)y
九州工業大学生命体工学研究科 飯久保 智
Magnetic fluctuations of Fe1+xSe0.45Te0.55 (x = 0, ) are investigated by using neutron scattering technique. Non-superconducting Fe1+Se0.45Te0.55 shows a pronounced magnetic fluctuation around a reciprocal lattice 2D vector Q2D = (0.5,0). On the other hand, superconductor FeSe0.45Te0.55 shows a magnetic fluctuation at Q2D = (0.5,0) and (0.5,±0.5). This result suggests that the AF fluctuations characterized by Q2D = (0.5,±0.5) may play an important role in superconductivity.
Appearance of unique strengthening mechanism of dental silver alloy by simple heat treatment
愛知学院大学歯学部 福井 壽男
The structure of a dental Ag-Pd-Cu-Au casting alloy has been studied various heat treatments. By SEM, TEM and XRD, the microstructure of as cast material is consisted of α１、α、and βphases. But, microstructure of solution treatment at 1123K change to α、β、and L10 type-ordered β‘phases. And, hardness increases drastically.
Toward Si-based high-efficiency thin-film solar cells using semiconducting silicides
筑波大学数理物質科学研究科 末益 崇
BaSi2, composed of abundant chemical elements, has advantages over other solar cell materials. It has a very large absorption coefficient of approximately 3×104cm-1 at 1.5eV. Furthermore, the band gap can be tune up to 1.4eV, matching the solar spectrum. We have focused on the epitaxial growth of BaSi2 films on Si(111), and achieved the external quantum efficiency of over 20%, the highest value ever reported for semiconducting silicides.
Structural designing of the magnetic anisotropy for the lanthanide-based single-molecule magnets
Single-molecule magnets (SMMs) are a class of metalorganic compounds, which show a slow magnetic relaxation due to magnetic anisotropy of the spin carrier(s). In the recent works, the use of heavy lanthanide ions is becoming popular because of their large spin multiplicity and large magnetic anisotropies in the ground state. We have developed the synthetic strategy to design the magnetic anisotropy, and synthesized an Er(III) SMM by the designing of anisotropy for the first time.