理學院
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學院概況
理學院設有數學系、物理學系、化學系、生命科學系、地球科學系、資訊工程學系6個系(均含學士、碩士及博士課程),及科學教育研究所、環境教育研究所、光電科技研究所及海洋環境科技就所4個獨立研究所,另設有生物多樣性國際研究生博士學位學程。全學院專任教師約180人,陣容十分堅強,無論師資、學術長現、社會貢獻與影響力均居全國之首。
特色理學院位在國立臺灣師範大學分部校區內,座落於臺北市公館,佔地約10公頃,是個小而美的校園,內含國際會議廳、圖書館、實驗室、天文臺等完善設施。
理學院創院已逾六十年,在此堅固基礎上,理學院不僅在基礎科學上有豐碩的表現,更在臺灣許多研究中獨占鰲頭,曾孕育出五位中研院院士。近年來,更致力於跨領域研究,並在應用科技上加強與業界合作,院內教師每年均取得多項專利,所開發之商品廣泛應用於醫、藥、化妝品、食品加工業、農業、環保、資訊、教育產業及日常生活中。
在科學教育研究上,臺灣師大理學院之排名更高居世界第一,此外更有獨步全臺的科學教育中心,該中心就中學科學課程、科學教與學等方面從事研究與推廣服務;是全國人力最充足,設備最完善,具有良好服務品質的中心。
在理學院紮實、多元的研究基礎下,學生可依其性向、興趣做出寬廣之選擇,無論對其未來進入學術研究領域、教育界或工業界工作,均是絕佳選擇。
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Item Enhanced Emission of (In, Ga) Nitride Nanowires Embedded with Self-assembled Quantum Dots(Wiley-VCH Verlag, 2008-03-25) C.-W. Hsu; A. Ganguly; C.-H. Liang; Y.-T. Hung; C.-T. Wu; G.-M. Hsu; Y.-F. Chen; Chia-Chun Chen; K.-H. Chen; L.-C. ChenWe report the structure and emission properties of ternary (In,Ga)N nanowires (NWs) embedded with self-assembled quantum dots (SAQDs). InGaN NWs are fabricated by the reaction of In, Ga and NH3 via a vapor–liquid–solid (VLS) mechanism, using Au as the catalyst. By simply varying the growth temperature, In-rich or Ga-rich ternary NWs have been produced. X-ray diffraction, Raman studies and transmission electron microscopy reveal a phase-separated microstructure wherein the isovalent heteroatoms are self-aggregated, forming SAQDs embedded in NWs. The SAQDs are observed to dominate the emission behavior of both In-rich and Ga-rich NWs. Temperature-dependent photoluminescence (PL) measurements indicate relaxation of excited electrons from the matrix of the Ga-rich NWs to their embedded SAQDs. A multi-level band schema is proposed for the case of In-rich NWs, which showed an anomalous enhancement in the PL peak intensity with increasing temperature accompanies with red shift in its peak position.Item Electronic Structures of Group-III-Nitride Nanorods Studied by X-ray Absorption, X-ray Emission, and Raman Spectroscopy(American Institute of Physics, 2006-05-29) C.-W. Pao; P.-D. Babu; H.-M. Tsai; J.-W. Chiou; S.-C. Ray; S.-C. Yang; F.-Z. Chien; W.-F. Pong; M.-H. Tsai; C.-W. Hsu; L.-C. Chen; Chia-Chun Chen; K.-H. Chen; H.-J. Lin; J.-F. Lee; J.-H. GuoNitrogen (N) and metal (Al, Ga, and In) K-edge x-ray absorption near-edge structure (XANES), x-ray emission spectroscopy (XES), and Raman scattering measurements were performed to elucidate the electronic structures of group-III–nitride nanorods and thin films of AlN, GaN, and InN. XANES spectra show slight increase of the numbers of unoccupied N p states in GaN and AlN nanorods, which may be attributed to a slight increase of the degree of localization of conduction band states. The band gaps of AlN, GaN, and InN nanorods are determined by an overlay of XES and XANES spectra to be 6.2, 3.5, and 1.9 eV, respectively, which are close to those of AlN and GaN bulk/films and InN polycrystals.Item Controlled Growth of Aluminium Nitride Nanorod Arrays via Chemical Vapour Deposition(IOP Publishing, 2006-06-14) J. Yang; T.-W. Liu; C.-W. Hsu; L.-C. Chen; K.-H. Chen; Chia-Chun ChenLarge-area and high-density arrays of AlN nanorods were synthesized at low temperature via a template-free and catalyst-free chemical vapour deposition. The quasi-aligned AlN nanorods were identified to grow along the c-axis and preferentially orient with their growth direction perpendicular to the substrate. Further studies showed that the AlN nanorods were grown on a buffer layer formed at the beginning of the reaction. By changing the flow rate of the carrier gas at the beginning of the reaction, we successfully obtained nanorods with different orientations on the substrate. The Raman spectrum and cathodoluminescence spectrum of the AlN nanorods at room temperature reveal the existence of oxygen-related defects in the nanorods.Item Self-Regulating and Diameter-Selective Growth of GaN Nanowires(IOP Publishing, 2006-06-14) C.-K. Kuo; C.-W. Hsu; C.-T. Wu; Z.-H. Lan; C.-Y. Mou; Y.-J. Yang; Chia-Chun Chen; K.-H. ChenWe report diameter-selective growth of GaN nanowires (NWs) by using mono-dispersed Au nanoparticles (NPs) on a ligand-modified Si substrate. The thiol-terminal silane was found to be effective in producing well-dispersed Au NPs in low density on Si substrates so that the agglomeration of Au NPs during growth could be avoided. The resultant GaN NWs exhibited a narrow diameter distribution and their mean diameter was always larger than, while keeping a deterministic relation with, the size of the Au NPs from which they were grown. A self-regulating steady growth model is proposed to account for the size-control process.Item Nanohomojunction (GaN) and nanoheterojunction (InN) nanorods on one-dimensional GaN nanowire substrates(Wiley-VCH Verlag, 2004-03-01) Z.-H. Lan; C.-H. Liang; C.-W. Hsu; C.-T. Wu; H.-M. Lin; S. Dhara; K.-H. Chen; L.-C. Chen; Chia-Chun ChenThe formation of homojunctions and heterojunctions on two-dimensional (2D) substrates plays a key role in the device performance of thin films. Accelerating the progress of device fabrication in nanowires (NWs) also necessitates a similar understanding in the one-dimensional (1D) system. Nanohomojunction (GaN on GaN) and nanoheterojunction (InN on GaN) nanorods (NRs) were formed in a two-step growth process by a vapor–liquid–solid (VLS) mechanism. Ga2O3 nanoribbons were formed using Ni as catalyst in a chemical vapor deposition (CVD) technique and then completely converted to GaN NWs with NH3 as reactant gas. An Au catalyst is used in the second step of the VLS process to grow GaN and InN NRs on GaN NWs using CVD techniques. A morphological study showed the formation of nanobrushes with different structural symmetries and sub-symmetries in both homogeneous and heterogeneous systems. Structural characterizations showed nearly defect-free growth of nanohomojunction (GaN) and nanoheterojunction (InN) NRs on 1D GaN NW substrates.Item Blueshift of yellow luminescence band in self-ion-implanted n-GaN nanowire(American Institute of Physics (AIP), 2004-05-03) S. Dhara; A Datta; C.-T. Wu; Z.-H. Lan; K.-H. Chen; Y. -L. Wang; Y.-F. Chen; C.-W. Hsu; L.-C. Chen; H.-M. Lin; Chia-Chun ChenOptical photoluminescence studies are performed in self-ion (Ga+)-implanted nominally dopedn-GaNnanowires. A 50 keV Ga+focused ion beam in the fluence range of 1×1014–2×1016 ions cm−2 is used for the irradiation process. A blueshift is observed for the yellow luminescence (YL) band with increasing fluence. Donor–acceptor pair model with emission involving shallow donor introduced by point-defect clusters related to nitrogen vacancies and probable deep acceptor created by gallium interstitial clusters is responsible for the shift. High-temperature annealing in nitrogen ambient restores the peak position of YL band by removing nitrogen vacancies.Item Growth Mechanism, Structure and IR Photoluminescence Studies of Indium Nitride Nanorods(Elsevier, 2004-08-15) Z.-H. Lan; W.-M. Wang; C.-L. Sun; S.-C. Shi; C.-W. Hsu; T.-T. Chen; K.-H. Chen; Chia-Chun Chen; Y.-F. Chen; L.-C. ChenHigh-quality single crystal indium nitride nanorods were grown on Si substrates by catalytic chemical vapor deposition. Both Raman and high resolution transmission electron microscopic analyses suggested that even a minute amount of oxygen, from the residual oxygen in the growth environment and/or native oxide on the Si, would effectively help the growth of InN nanorods. The In2O3 formed on Au nanoparticles helped dissolve nitrogen as a catalyst with the subsequent growth of InN nanorods. Variations in the apparent color and photoluminescence (PL) spectra of the InN nanorods were observed. For the optically brown InN nanorods that exhibited diameters in the range of 30–50 nm, the PL study showed a peak at 1.9 eV, the possible origins of which are discussed. In contrast, for the optically black InN nanorods that exhibited diameters in the range of 50–100 nm, the PL peak at approximately 0.766 eV measured at 20 K was attributed to band edge emission.Item Hexagonal-to-Cubic Phase Transformation in GaN Nanowires by Ga+ Implantation(American Institute of Physics (AIP), 2004-06-28) S. Dahara; A. Datta; C.-T. Wu; Z.-H. Lan; K.-H. Chen; Y. -L. Wang; C.-W. Hsu; C.-H. Shen; L.-C. Chen; Chia-Chun ChenHexagonal to cubic phase transformation is studied in focused ion beam assisted Ga+-implanted GaNnanowires. Optical photoluminescence and cathodoluminescence studies along with high-resolution transmission electron microscopic structural studies are performed to confirm the phase transformation. In one possibility, sufficient accumulation of Ga from the implanted source might have reduced the surface energy and simultaneously stabilized the cubic phase. Another potential reason may be that the fluctuations in the short-range order induced by enhanced dynamic annealing (defect annihilation) with the irradiation process stabilize the cubic phase and cause the phase transformation.Item Electronic Structure of GaN Nanowire Studied by x-ray-Absorption Spectroscopy and Scanning Photoelectron Microscopy(American Institute of Physics(AIP) Publishing, 2003-06-02) J.-W. Chiou; J.-C. Jan; H.-M. Tsai; W.-F. Pong; M.-H. Tsai; I.-H. Hong; R. Rklauser; J.-F. Lee; C.-W. Hsu; H.-M. Lin; Chia-Chun Chen; C.-H. Shen; L.-C. Chen; K.-H. ChenX-ray absorption near edge structure (XANES) and scanning photoelectron microscopy (SPEM) measurements have been employed to obtain information on the electronic structures of the GaN nanowires and thin film. The comparison of the XANES spectra revealed that the nanowires have a smaller (larger) N (Ga) K edge XANES intensity than that of the thin film, which suggests an increase (decrease) of the occupation of N 2p (Ga 4p) orbitals and an increase of the N (Ga) negative (positive) effective charge in the nanowires. The SPEM spectra showed that the Ga 3d band for the nanowires lies about 20.8 eV below the Fermi level and has a chemical shift of about -0.9 eV relative to that of the thin film. © 2003 American Institute of Physics.Item Characterization of Nanodome on GaN Nanowires Formed with Ga Ion Irradiation(Nihon Kinzoku Gakkai, 2004-01-01) S. Muto; S. Dahara; A. Datta; C.-W. Hsu; C.-T. Wu; C.-H. Shen; L. -C. Chen; K.-H. Chen; Y.-L. Wang; T. Tanabe; T. Maruyama; H.-M. Lin; Chia-Chun ChenStructure of nano-domes formed by Ga+ ion irradiation with a focused ion beam (FIB) apparatus onto GaN nanowires (NWs) was examined with conventional transmission electron microscopy (CTEM), electron energy-loss spectroscopy (EELS) and energy-filtering TEM (EF-TEM). The nano-dome consisted of metallic gallium, covered by a GaN layer, the structure of which is amorphous or liquid. It is considered that the dome structure is formed by preferential displacement of lighter element (N) and agglomeration of heavier one (Ga). 1 MeV electron irradiation onto the sample pre-irradiated by Ga+ ions at a dose below the threshold for the dome formation induced the N2 bubble formation without segregating Ga atoms, which suggests the radiation-enhanced diffusion (RED) of heavy atoms plays an important role in the nano-dome formation.