Transient phases and their transition temperatures of a-Si in non-isothermal processes

The heating rate dependence of the phase transition temperature was formulated based on the temperature dependence of nucleation of a new phase. The glass transition temperature of a-Si was explained in terms of van der Waals fluid of a-Si pseudo-molecules which are produced by the fragmentation of continuous random networks of Si atoms. Transient phases and their transition temperatures as a function of the heating rate are summarized in the phase diagram

非晶質半導体の超音波伝搬による光変調現象と音響記憶現象の研究

金沢大学工学部研究課題/領域番号:X00090----355140研究期間(年度):1978 – 1979出典：「非晶質半導体の超音波伝搬による光変調現象と音響記憶現象の研究」研究成果報告書　課題番号X00090----355140（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-X00090----355140/）を加工して作

線状ガス炎によるpoly-Si TFT策性用急速高温アニール装置の試作

金沢大学工学部線状ガス炎による高温アニールは、poly-Siの電気的特性の改善に目覚しい効果をもたらすことが確認された。改善の原因は、高温アニールによってSecondary Grain Growth(S.G.G)が起こり結晶粒中の欠陥密度が減少すること、および各種の欠陥の巣窟である結晶粒界が縮小することによるものであると結論される。即ち、TED,TEM測定から顕著なS.G.Gが観測され、ESR測定によりスピン密度が大幅に減少するので、グレインの結晶性の改善と結晶粒界の縮小とが予測されるわけである。各種濃度の不純物がドープされたpoly-Siについても線状ガス炎高温アニールの効果を調べたところ、non-dopeの試料に比べより顕著なS.G.G.が起こることが観測された。そこで、van der Paw法によりHall移動度を求めたところ燐をドープした試料で70cm/V・sを超す値が得られた。以上述べたように、線状ガス炎高温アニールはpoly-Siの高品質化に非常に有効であることが立証されたが、現状では試料をガス炎中を通過させる際に試料の温度が次第に上昇するという欠点がある。従って、熱処理した試料の均一性に問題がある。現在、この点について改良を進めており、まもなく解決の見通しが得られている。初年度としては、予想以上の成果が得られたと考えられる。研究課題/領域番号:07555413, 研究期間(年度):1995 – 1996出典：研究課題「線状ガス炎によるpoly-Si TFT策性用急速高温アニール装置の試作」課題番号07555413（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07555413/）を加工して作

Model for the glass transition in amorphous solids based on fragmentation

A model for the glass transition in a heating process has been proposed. In the model, noncrystalline solids are assumed to be assemblies of pseudomolecules or structural units. When the noncrystalline solid is heated, a bond breaking process becomes dominant compared with a rebinding process of broken bonds. At high temperature, successive bond breaking causes the fragmentation of the solid and the fragment size becomes smaller as the temperature further increases. Consequently, the solid begins to show some viscous behavior when the fragment size reaches a critical value. To construct mathematical expressions for the fragmentation model, we employed a simple rate equation for the bond breaking process first and then obtained the temperature dependence of dangling bond density in a noncrystalline solid. Second, the expressions for the fragment density and size as a function of temperature were obtained based on the following assumptions: (1) bond breaking takes place mainly at the boundaries between pseudomolecules, (2) once buds of microcracks are generated, successive bond breaking occurs mostly at the tip of the microcracks, and (3) the fragments are Voronoy polyhedra. Finally, the diffusion coefficient in the system was obtained by assuming the vacancy mechanism in solids and then the temperature dependence of viscosity was derived through Stokes-Einstein relation. To examine the present model, applications of the model to the phase changes of α-Si in heating processes are carried out and the results were discussed

バイアススパッタによるシリコン薄膜太陽電池製作の基礎研究

金沢大学工学部研究課題/領域番号:56045055, 研究期間(年度):1981出典：「バイアススパッタによるシリコン薄膜太陽電池製作の基礎研究」研究成果報告書　課題番号56045055（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-56045055/）を加工して作

非晶質半導体の超音波伝搬による光変調現象の研究

金沢大学工学部研究課題/領域番号:X00090----255117, 研究期間(年度):1977出典：「非晶質半導体の超音波伝搬による光変調現象の研究」研究成果報告書　課題番号X00090----255117（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-X00090----255117/）を加工して作

Spectral responses of GaAs photodiodes fabiricated by rapid thermal diffusion

The spectral responses of GaAs photodiodes fabricated by rapid thermal diffusion (RTD) of Zn are presented. The authors tried controlling the p+-n junction depth by the heating rate of RTD, without extending the diffusion time. It is found that Zn diffuses from the surface to a deeper position as the heating rate increases. Consequently, the spectral response of photodiodes formed by RTD is strongly dependent on the heating rate of RTD. A large improvement in the short-wavelength response between 400 and 800 nm is observed as the heating rate decreases

High speed crystallization of a-Si by lateral sweep annealing in steep temperature gradient

The a-Si films deposited on quartz substrates were crystallized by lateral sweep annealing in steep temperature gradient using a gas burner. Random nucleation in amorphous region was effectively suppressed in the temperature gradient, so lateral solid phase epitaxial growth from crystallites generated at the initial stage of lateral sweep annealing spread over 100 µm. Their crystallographic orientations were mostly (100)

Structural phase transitions and lean NO removal activity of copper-modified alumina

Copper-modified alumina catalysts, designed for NO removal under lean-burn engine conditions, have been investigated from the viewpoint of the structural phase transition and thermal stability. The structural changes of crystalline components heat-treated at temperatures from 500{degrees}C to 1100{degrees}C were characterized by neutron diffraction (ND) method. In the as-prepared materials, powder-diffraction patterns revealed a mixture of crystalline {gamma}-Al{sub 2}O{sub 3} and CuO, and electron spin resonance (ESR) data showed well-dispersed Cu{sup 2+} cations coordinated by O atoms in an open-octahedron geometry. ND measurements confirmed the elimination of the CuO phase above 800{degrees}C, and suggested the stabilization of a {delta}-phase of alumina by 10 mol% CuO-doping at 900-1000{degrees}C. This Cu-alumina catalyst which was subjected to heat treatment at 900{degrees}C in air showed a 20% lean de-NOx removal efficiency in a test using a model exhaust gas mixture of space velocity =00, 000 h{sup -1}