Browsing by Author "Hsu, K. Y."

Now showing 1 - 12 of 12

Atomic layer deposition prepared Al-doped ZnO for liquid crystal displays applications
(2018-05-01)
Su, Y. C.
;
Chiou, C. C.
;
Marinova, V.
;
Lin, S. H.
;
Bozhinov, N.
Aluminum-doped zinc oxide (AZO) layers are prepared by using atomic layer deposition technique. The obtained layers possess high optical transmittance at visible and near-infrared spectral range. By varying the Al content, optimal growth compositions of AZO are established where the electrical conductivity of the film is highest. Based on performed optical and electrical characteristics measurements, selected AZO films with optimal conductivity are implemented as transparent electrodes in liquid crystal display devices. The electro-optical modulation characteristics of these devices are found to be comparable to those of devices using commercial ITO electrodes.
center dot-ray induced effects in Sm-doped strontium borate glasses
(2013)
Marinova, V.
;
Tomov, V.
;
Chuang, C. I.
;
Lin, Y. C.
;
Lin, S. H.
Strontium borate glasses SrB4O7 doped with Sm ions are prepared by conventional melting-quenching method. The effect of center dot-ray irradiation on the glass samples is studied by measuring the absorption spectra and the photoluminescence. It is found that the center dot -ray irradiation caused partial reduction of Sm3+ to Sm2+ at room temperature. Borate framework is supposed to be responsible for the Sm3+ to Sm2+ transition.
Characterization of doped Bi4Ge3O12 single crystals by light-induced absorption, electrical and photoelectrical measurements
(2007-02-01)
Petrova, D.
;
Marinova, V.
;
Liu, R. C.
;
Lin, S. H.
;
Hsu, K. Y.
Measurement of light-induced absorption changes, dark- and photoconductivity have been performed on Bi4Ge3O12 crystals doped with Fe, Rh and Fe+Rh. All samples exhibited a strong photochromic effect at room temperature, which was fully reversible after thermal annealing. It was found that Rh-doped Bi4Ge3O12 crystals possess a lower dark conductivity (sigma(d) = 5.2 x 10(-14) (Omega.cm)(-1)) at room temperature in comparison with other investigated samples. New centers in the Bi4Ge3O12 inter-band structure, with thermal activation energies between 0.25 and 0.37 eV, have been created by doping with Fe and Rh. Fe-doped and Fe+Rh co-doped samples showed a non-linear photoconductivity dependence on light intensity, under illumination with a 514-nm laser.
Light-induced and holographic properties of ruthenium and manganese co-doped Bi(4)Ge(3)O(12) crystals
(2010-07-01)
Lin, S. H.
;
Marinova, V.
;
Lin, Y. C.
;
Petrova, D.
;
Chou, W. C.
The effect of Ru + Mn co-doping on the light-induced properties of Bi(4)Ge(3)O(12) (BGO) crystals is studied and compared with single Ru- and Mn-doped crystals. Optical absorption spectra of Ru + Mn co-doped crystal demonstrates a photosensitivity shift to the visible spectral range. In addition, a strong photochromic effect, being fully reversible by thermal annealing is observed. It is verified by photoluminescence emission that charge traps could be manipulated under ultraviolet (UV) excitation, as the photoluminescence intensity decreases revealing the existence of the state filling effect. Ru + Mn doping leads to a faster response time during holographic recording at 633 nm and a prolonged read-out process, especially after a preliminary exposure to UV light. The ability to modify the defect structure and corresponding absorption bands suggests the future potential for optical fixing using a two-step sensitization method.
Light-induced and holographic properties of ruthenium and manganese co-doped Bi4Ge3O12 crystals
(2010-07-01)
Lin, S. H.
;
Marinova, V.
;
Lin, Y. C.
;
Petrova, D.
;
Chou, W. C.
The effect of Ru + Mn co-doping on the light-induced properties of Bi4Ge3O12 (BGO) crystals is studied and compared with single Ru- and Mn-doped crystals. Optical absorption spectra of Ru + Mn co-doped crystal demonstrates a photosensitivity shift to the visible spectral range. In addition, a strong photochromic effect, being fully reversible by thermal annealing is observed. It is verified by photoluminescence emission that charge traps could be manipulated under ultraviolet (UV) excitation, as the photoluminescence intensity decreases revealing the existence of the state filling effect. Ru + Mn doping leads to a faster response time during holographic recording at 633 nm and a prolonged read-out process, especially after a preliminary exposure to UV light. The ability to modify the defect structure and corresponding absorption bands suggests the future potential for optical fixing using a two-step sensitization method.
Liquid crystal cell with graphene electrodes
(2017-01-01)
Marinova, V.
;
Tong, Z. F.
;
Petrov, S.
;
Lin, S. H.
;
Chen, M. S.
We demonstrate a graphene-based nematic liquid crystal cells fabricated by photo alignment technique. The modulation characteristics have been measured revealing that photo alignment method shows great potential for protecting the graphene layer on glass substrate during LC device fabrication.
Liquid crystal electro-optic modulator based on transparent conductive TiO2/Ag/TiO2 multilayers
(2018-06-01)
Su, Y. C.
;
Chiou, C. C.
;
Marinova, V.
;
Lin, S. H.
;
Dikov, Hr.
In this paper, TiO2/Ag/TiO2 multilayers, deposited by magnetron sputtering technique at room temperature are used as transparent conductive layers for Liquid Crystal (LC) devices fabrication. The measured electro-optical modulation characteristics and phase retardation of LC cell based on TiO2/Ag/TiO2 electrode show improved electro-optic performances in comparison with LC reference cell using commercial Indium Tin Oxide (ITO). Low sheet resistance and high transparency of TiO2/Ag/TiO2 multilayers open a great potential for next generation ITO-free liquid crystals electro-optical modulators.
Liquid crystal light valve operating at near infrared spectral range
(2016-04)
Marinova, V.
;
Chi, C. H.
;
Tong, Z. F.
;
Liu, R. C.
;
Berberova, N.
A near infrared sensitive liquid crystal light valve, based on Ru-doped Bi12TiO20 (BTO:Ru) inorganic crystal and liquid crystal is proposed. The two-beam mixing experiments at Raman-Nath regime show promising gain value at 1064 nm. An image evolution through the proposed device is demonstrated supporting all optical switching property.
Preparation and characterization of Irgacure 784 doped photopolymers for holographic data storage at 532 nm
(2009-02-01)
Lin, S. H.
;
Hsiao, Y-N
;
Hsu, K. Y.
;
電子物理學系
;
光電工程學系
This paper presents the development of a thick photopolymer for holographic data storage at a wavelength of 532 nm. Irgacure 784, one kind of the titanocene photoinitiators, has been selected and doped to synthesize the photopolymers in this research. Using a two-step thermo-polymerization procedure two photopolymer samples have been fabricated, Irgacure 784 doped poly(methyl methacrylate) (PMMA) and Irgacure 784 doped epoxy resin. Samples of 2 mm thick have been fabricated. Holographic measurements show that Irgacure 784 doped epoxy resin is very sensitive at 532 nm and that it is capable of supporting holographic data storage at a ultra-fast recording rate of 760 Mb s(-1). Mass spectrum measurement, solid state 1H-NMR spectrum measurement, and thermogravity analyses (TGA) have been performed. The results reveal the physical mechanism of holographic recording in these samples, providing a guideline for a design strategy and fabrication technique to produce a low-shrinkage recording material for holographic data storage in the tera-byte information age.
The influence of Rh doping on the light-induced properties of Bi(4)Ge(3)O(12) single crystals
(2009-01-01)
Marinova, V.
;
Petrova, D.
;
Lin, S. H.
;
Hsieh, M. L.
;
Hsu, K. Y.
The influence of different doping concentrations of rhodium on the light-induced and holographic properties of BGO crystal is investigated. It is found that Rh addition generates sufficient density of traps for photoinduced charge carriers such that holographic gratings are successfully recorded in the blue-green spectral range. The measured steady state diffraction efficiency at 514 nm is 0.14%, which corresponds to a refractive index modulation of Delta n similar to 1.5 x 10(-6) for higher Rh concentration. A photochromic effect and nonlinear dependence of photoconductivity on light intensity are observed indicating deep level and shallow level contributions to the charge transport mechanism of Rh-doped BGO.
The influence of Rh doping on the light-induced properties of Bi4Ge3O12 single crystals
(2009-01-01)
Marinova, V.
;
Petrova, D.
;
Lin, S. H.
;
Hsieh, M. L.
;
Hsu, K. Y.
The influence of different doping concentrations of rhodium on the light-induced and holographic properties of BGO crystal is investigated. It is found that Rh addition generates sufficient density of traps for photoinduced charge carriers such that holographic gratings are successfully recorded in the blue-green spectral range. The measured steady state diffraction efficiency at 514 nm is 0.14%, which corresponds to a refractive index modulation of Delta n similar to 1.5 x 10(-6) for higher Rh concentration. A photochromic effect and nonlinear dependence of photoconductivity on light intensity are observed indicating deep level and shallow level contributions to the charge transport mechanism of Rh-doped BGO.
Wide-Range Tuning of the Mo Oxidation State in La1-xSrxFe2/3Mo1/3O3 Perovskites
(2016-06)
Istomin, Sergey Ya.
;
Chernova, Varvara V.
;
Antipov, Evgeny V.
;
Lobanov, Maxim V.
;
Bobrikov, Ivan A.
La1-xSrxFe2/3Mo1/3O3 (0x1) perovskites allow exceptionally wide tuning of the Mo oxidation state from +3 (x = 0) to +6 (x = 1) with the Fe-III oxidation state virtually unchanged. The end members of this series show antiferromagnetic ordering in LaFe2/3Mo1/3O3 at T-N = 520 K and ferrimagnetic ordering in SrFe2/3Mo1/3O3 at T-C = 420 K. The crucial role of electron correlations in the Mo 4d shell suggests that LaFe2/3Mo1/3O3 with a half-filled band is a Mott insulator, whereas SrFe2/3Mo1/3O3 is a band insulator. In both cases, the magnetic structure is dictated by antiferromagnetic superexchange between localized magnetic moments. At intermediate compositions, an interplay of antiferromagnetic-superexchange and double-exchange interactions results in nonmonotonous variations of both the magnetic-ordering temperature and saturation magnetization.