Browsing by Author "Lyu, Yang-Ru"

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A characterization on emission property of In2O3-SiO2 nanocomposite thin films
(2013-09-01)
Lyu, Yang-Ru
;
Hsieh, Tsung-Eong
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Nanocomposite thin films containing finely dispersed, crystalline In2O3 nanoparticles embedded in SiO2 matrix were fabricated by target-attachment sputtering method. Transmission electron microscopy observed single crystalline In2O3 nanoparticles uniformly embedded in SiO2 matrix of the samples with In2O3 content less than about 60 vol.%. Photoluminescence spectra of the In2O3-SiO2 nanocomposite samples were found to comprise of the blue, green and red emissions. Analytical results indicated that the red and green emissions are correlated to the transitions from conduction band (CB) edge to the In-i(center dot center dot center dot) and V-In''' defect levels, respectively, while the blue emission is originated from the transition from CB edge to V-o(center dot center dot) level or from Vo level to the valence band edge. (C) 2012 Elsevier B.V. All rights reserved.
Photoluminescence Characteristics of In2O3 Quantum Dot (QD)-SiO2 Nanocomposite Thin Films Containing Various QD Sizes
(2012)
Lyu, Yang-Ru
;
Hsieh, Tsung-Eong
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Nanocomposite layers containing In2O3 quantum dots (QDs) with radii ranging from 1.8 to 5 nm embedded in SiO2 matrix were prepared. Prominent blueshift with a drastic increase in emission efficiency for red, green and blue emissions were observed in the photoluminescence (PL) spectra of samples when QD radius was less than 1.32 nm. PL enhancement was further confirmed by the calibration of defect trap levels and indicated the Bohr radius of In2O3 QDs was 1.32 nm. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.007202ssl] All rights reserved.
The effect of dielectric confinement on photoluminescence of In2O3-SiO2 nanocomposite thin films incorporated by nitrogen
(2013-05-14)
Lyu, Yang-Ru
;
Hsieh, Tsung-Eong
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Nanocomposite thin films containing In2O3 nanoparticles were prepared by the target-attachment sputtering utilizing the InN pellets and allowing the N-2 inlet gas flow during the deposition process. The x-ray photoelectron spectroscopy revealed that the chemical composition of In2O3 nanoparticles becomes InOxNy and the SiOxNy phase forms in the matrix of nanocomposite layer. Photoluminescence analysis indicated that the dielectric confinement effect induced by the N-incorporation tends to restrain the green emission of nanocomposite layers due to the presence of surface polarization on nanoparticles. Suppression of blue emission was also observed due to the elimination of oxygen vacancies in In2O3 nanoparticles. Furthermore, the N elements might occupy the oxygen lattice sites and generate a new defect level, N-O(-), to induce the violet emission. Analytical results confirmed the mechanisms of green and blue emissions of the nanocomposite thin films containing In2O3 nanoparticles reported previously. (C) 2013 AIP Publishing LLC.
The Photoluminescence Properties of Nanocomposite Thin Films Containing InN Quantum Dots Embedded in Si Matrix
(2014-01-01)
Lyu, Yang-Ru
;
Hsieh, Tsung-Eong
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Nanocomposite thin films containing indium nitride (InN) quantum dots (QDs) embedded in silicon (Si) matrix were prepared by the target-attachment sputtering method. X-ray photoelectron spectroscopy confirmed the presence of hexagonal InN phase in the samples and transmission electron microscopy revealed the single-crystalline InN QDs with the diameters ranging from 3.0 to 5.6 nm finely dispersed in Si matrix. The room-temperature photoluminescence (PL) analysis observed a sole emission with the peak at about 1155 nm (similar to 1.08 eV) for all samples in the measured wavelength range of 900 to 1600 nm. Such a PL emission was ascribed to the pinning effect of conduction band at the Fermi stabilization level of InN. Further, the PL intensity increased with the increase of incident laser power, implying the PL emission is correlated with the band-to-band transition in InN. The low-temperature PL analysis observed the dramatic increase of PL intensity and the shift of peak location toward the short wavelength side when the temperature was decreased. Meanwhile, the symmetry of emission peaks gradually improved owning to the suppression of the band tailing and thermal population effects. (C)2014 The Electrochemical Society. All rights reserved.