http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Fill factor controlled nanoimprinted ZnO nanowires based on atomic layer deposition
Surabhi, Srivathsava,Luong, Chi Hieu,Kim, Min Yi,Van, Phuoc Cao,Quoc, Viet Dong,Kuchi, Rambabu,Lee, Jae-Woong,Chang, Hyo-Sik,Jeong, Jong-Ryul ELSEVIER 2018 Current Applied Physics Vol.18 No.6
<P><B>Abstract</B></P> <P>Enhanced diffraction by sub-wavelength nanostructures to convert incident electromagnetic radiation into waveguide modes has applications in anti-reflective coatings for optoelectronic devices. We propose a metal oxide (ZnO) nanowire grid polarizer as such a nanostructure, fabricated by ultraviolet nanoimprint lithography and whose fill factor (FF) is controlled by atomic layer deposition. Using finite difference time domain simulations, we investigated the polarization-dependent optical transmittance of the structures and calculated the polarizing efficiency. Optical profiles such as electric and magnetic field intensity and current density distributions of specific FF nanopatterns were determined for the transverse magnetic and transverse electric modes. The effects of geometrical parameters including the wire-grid period, fill ratio, and spacing between the wire-grid layers on diffraction wavelength were characterized. Respective FF-controlled ZnO nanowire structures were fabricated and their experimental optical transmittances were measured for nanowire grid polarizer applications.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Fill factor (FF) controlled ZnO nanowires (NW) through atomic layer deposition (ALD), combined with UV-NIL were prepared. </LI> <LI> Polarizing efficiency of NWs has increased with ALD thickness at which stronger diffraction wavelengths are observed. </LI> <LI> ALD enables us to control the fill factor precisely in nanowire grid polarizer. </LI> <LI> Simulation results supported by experiments confirm that the proposed FF controlled ZnO NWs can be efficient polarizers. </LI> </UL> </P>
Fill factor controlled nanoimprinted ZnO nanowires based on atomic layer deposition
Srivathsava Surabhi,Chi Hieu Luong,김민이,Phuoc Cao Van,Viet Dongquoc,Rambabu Kuchi,이재웅,장효식,정종율 한국물리학회 2018 Current Applied Physics Vol.18 No.6
Enhanced diffraction by sub-wavelength nanostructures to convert incident electromagnetic radiation into waveguide modes has applications in anti-reflective coatings for optoelectronic devices. We propose a metal oxide (ZnO) nanowire grid polarizer as such a nanostructure, fabricated by ultraviolet nanoimprint lithography and whose fill factor (FF) is controlled by atomic layer deposition. Using finite difference time domain simulations, we investigated the polarization-dependent optical transmittance of the structures and calculated the polarizing efficiency. Optical profiles such as electric and magnetic field intensity and current density distributions of specific FF nanopatterns were determined for the transverse magnetic and transverse electric modes. The effects of geometrical parameters including the wire-grid period, fill ratio, and spacing between the wire-grid layers on diffraction wavelength were characterized. Respective FF-controlled ZnO nanowire structures were fabricated and their experimental optical transmittances were measured for nanowire grid polarizer applications.
Thanh Son Vo,Srivathsava Surabhi,Chi Hieu Luong,윤순길,이경동,박병국,정종율 한국물리학회 2015 Current Applied Physics Vol.15 No.7
In this study, we have systematically investigated a magnetic resonance absorption and tunability of absorption wavelength in isolated metal-insulator-metal (MIM) nanodot arrays with transmission geometry. The elemental electromagnetic resonances and their hybridizations are studied using 3- dimensional finite-difference time-domain (FDTD) calculation and resonance properties including the resonance peak tunability, magnetic permeability and quality (Q) factor are characterized with respect to the coupling strength. We have found the existence of electric and magnetic resonance mode in the MIM (Au/MgF2/Au) structure and the magnetic resonance has larger wavelength tunability than the electric resonance. The absorption cross section calculation revealed that absorption is the dominant extinction process at the magnetic resonance only. Magnetic permeability (m) calculations for the various MIM parameters showed the maximum value of the imaginary part of μ is 16.1 with Q factor of 9.2 when the size of nanodot is 200 nm and the inter-dot distance is 300 nm. The presented calculations can be used to tune the response of the magnetic resonance absorption with a variable resonance wavelength and Q factor by using the simple MIM structures with transmission geometry.
Soo-Dong Kim,Srivathsava Surabhi,Jihoon Choi,Jong-Ryul Jeong 대한금속·재료학회 2019 ELECTRONIC MATERIALS LETTERS Vol.15 No.6
Monodisperse silica particles were fabricated by seed synthesis and growth using two-phase synthesis methods and additionalgrowth methods based on the Stöber process. The particle size and monodispersity of the silica particles were investigatedby changing the reaction time and reactant concentration during seed growth. At the beginning of seed growth, small andlarge particles were present at the same time; however, the size became more uniform as the reaction proceeded. When thestirring conditions were constant, the size of the silica particles was constant, despite variations in the reactant concentration. Relatively simple methods of manufacturing photonic crystal films via the self-assembly of monodisperse silica particles ina regular lattice were demonstrated. Using photocurable colloidal suspensions, practical methods are presented to producecolloidal photonic crystals with high optical transparency and physical stiffness.
Broadband tunable plasmonic substrate using self-assembled gold–silver alloy nanoparticles
Phuoc Cao Van,Srivathsava Surabhi,Viet Dongquoc,이재웅,태청천,kuchirambabu,정종율 한국물리학회 2019 Current Applied Physics Vol.19 No.11
In the present work, a facile approach of Au–Ag alloy NPs fabrication is proposed for plasmonic inclusion applicative studies. These hybrid NPs were prepared by the sequential deposition of Ag, Au layers on a glass substrate via RF-sputtering followed by high-temperature annealing. Compositional and size controllability of the NPs was attained by changing the ratio of nominal thicknesses of the respective Au, and Ag layers during the deposition. LSPR red (blue) peak shift occurs with increasing layer thickness Au (Ag) signifying the peak sensitivity. The influence of geometrical, compositional, and background media for achieving LSPR-sensitivity is examined and validated by FDTD simulation studies. With the agreeable peak shift tendencies, the proposed study of broadband tunable LSPR-sensitivity is expected to provide a framework for a wide range of plasmonic applications.
Lee, Sung Woo,Surabhi, Srivathsava,Kuchi, Rambabu,Sohn, Youngku,Jeong, Jong-Ryul Elsevier 2019 Journal of alloys and compounds Vol.771 No.-
<P><B>Abstract</B></P> <P>Revealing detailed catalytic and magnetic properties and the corresponding structural changes of Fe oxide materials are extremely important for their diverse applications. For this, magnetic properties of thermally phase transformed β-FeOOH nanorods (NRs) (to porous α-Fe<SUB>2</SUB>O<SUB>3</SUB>) were examined in the temperature up to 550 °C. The thermal treatment enhances the lattice strain (ε) that facilitates in creating pore structures. Fundamental physicochemical properties were examined by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), diffuse reflectance UV–visible absorption spectroscopy, and X-ray photoelectron spectroscopy (XPS). An average size of pores and pore-size distribution were characterized by Brunauer-Emmett-Teller (BET) surface area analysis. Temperature and field dependent magnetic properties of calcination samples were investigated by vibrating sample magnetometer (VSM) for understanding the morphology-dependent magnetic behavior of NRs. The phase transformation behavior of these thermally treated magnetic NRs was analyzed through magnetic property characterization by considering all possible relationships with lattice strain effects, oxygen vacancies, magnetic, and morphology anisotropy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Porous α-Fe<SUB>2</SUB>O<SUB>3</SUB> NRs obtained under thermal treatment via strain induced structural phase transformation of β-FeOOH.. </LI> <LI> Systematic characterization and analysis provided for the phase transformation of β-FeOOH. </LI> <LI> Surface area, porosity and defects have significant role on the magnetic properties of NRs. </LI> <LI> The surface OH groups, lattice strain of NRs have been effected the CO oxidation rate. </LI> </UL> </P>