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5/13專題演講公告

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日期:2013/05/13(星期一)
時間:自10時20分至12時10分
演講地點(地址):工綜館B03

日期:2013/05/13(星期一)
時間:自10時20分至12時10分
演講地點(地址):工綜館B03
演講者:翁明壽 教授
演講者服務單位:國立東華大學材料科學與工程學系

演講題目:
Preparation and characterization of multifunctional thin films of vapor-deposited titanium oxides and related materials

摘要:
As a versatile multifunctional material, titania (TiO2) and related materials have emerged as one of the most fascinating materials in the modern era, capturing the attention of scientists and engineers in exploring distinctive properties for promising applications. The applications range from photovoltaics, photocatalysis, photo-/electrochromics, transparent conducing oxide, sensors to ferromagnetism. Titania (anatase) is the best photocatalyst under UV light irradiation and is also the best photo-anode in dye-sensitized solar cells (DSSC); when doped with Nb or other elements, it becomes a promising transparent conducting oxide (TCO) and a ferromagnetic material for dilute magnetic semiconductor (DMS). To explore their novel properties and applications, various innovative processing methods have been used to prepare many new titania based materials of different composition, phase, crystallinity, structures or forms, including pure TiO2, anion- and cation-doped TiO2, and sculptured mesoporous titania.
Materials such as pristine and doped ZnO, SnO2, In2O3 and TiO2 have been investigated on the development of room-temperature ferromagnetism (RTFM) during the past decade, but the microscopic mechanism of long-range order magnetic behavior for the oxides is still an open problem. RTFM is observed in annealed pure TiO2 and various transition metal doped titania including niobium doped titania (TNO) thin films. Both the as-deposited amorphous films were amorphous and only when annealed under specific window of conditions, they became ferromagnetic with saturation magnetization (Ms) up to~60 emu/cm3. The values of Ms are affected by film thickness, annealing temperature, atmosphere and time, dopant, etc. For the films exhibited the maximum Ms value in a series of films, their XRD, XPS and Raman spectra, morphology, grain size are significantly different from the rest of films and the difference could be caused by oxygen vacancies and by quantum size effects. The results demonstrated that the RTFM in the titania films are affected primarily by the interfaces between the nano-grains with sizes comparable to quantum dots and secondarily by the oxygen vacancies.

學歷

     

畢業學校

國別

主修學門系所

學位

Marquette University

美國

材料科學及冶金

Ph.D

Marquette University

美國

材料科學及冶金

M.S.

國立清華大學

台灣

Materials

B.S.

經歷:

     

服務機關

服務部門

職稱

 

國立東華大學

理工學院

院長

國立東華大學

Northwestern University

Dept. of Materials Sci.& Eng.

Visiting Professor

Northwestern University

國立東華大學

材料科學與工程學系

教授兼系主任

國立東華大學

國立東華大學

材料科學與工程學研究所

教授兼所長

國立東華大學

Northwestern University

BIRL Industrial Research Lab.

Sr. Scientist

Northwestern University

Prog. Manager

   

Prog. Manager

Northwestern University

Materials Res. Center & Dept. MSE

Protdoc

Northwestern University

Marquette University

Materials Science Program

TA/RA

Marquette University