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With the increase in dimensions of optical elements in addition to ever rising demand for aspherical optics, the millimeter-scale periodic waviness that is naturally produced by machining (such as diamond turning) process in precision optical engineering has been one of the most crucial issues in the development of high surface quality optical elements. Even an extremely small waviness can affect the laser beam profile significantly through interference caused by Bragg scattering. This paper presents a novel method for improving a laser beam profile by utilizing the characteristics of Bragg scattering without requiring established final surface finishing processes such as optical polishing. By engraving an artificial periodic structure with a period of a few hundred microns, the Bragg scattering angle that influences the formation of interference fringes in the laser beam profile was drastically enlarged. Consequently, the quality of the beam profile was improved at a propagation distance where the 0th and 1st (− 1st) order beam modes are spatially separated, only by diamond turning machining without the surface finishing process. In addition, this approach represents an important contribution to green technology, which seeks energy saving and waste reduction in the optical surface manufacturing process.

This publisher’s note contains corrections to Opt. Lett. 46, 4216 (2021)OPLEDP0146-959210.1364/OL.432413.

Wavelength-tunable optical vortices with a topological charge equal to l = 1 of orbital angular momentum (OAM) were experimentally realized using a single off-axis spiral phase mirror (OSPM) with lasers of various visible-light wavelengths. Using an OSPM designed for 561 nm and an incidence angle of 45°, circular doughnut-shaped l = 1 optical vortices were obtained at 561, 473, and 660 nm by rotating the OSPM to modify the laser incidence angle. Wavelength-tunable l = 1 optical vortices were obtained at the respective incidence angles of 45°, 53.4°, and 33.7°, because the effective geometrical thickness of the OSPM, which determines the order of OAM, was identical at each wavelength. This flexible OSPM which operates over a wide wavelength range will provide continuously wavelength-tunable optical vortices for applications in the fields of advanced optics and photonics in which optical vortices with wide wavelength tunability are in demand.

With an increase in the size and shape complexity of optical surfaces, the periodic structure on the optical surface can have significant effects on the beam profile, which propagates in the optical system. This necessitates a quantitative analysis of the interference between diffracted beam modes formed on the propagating beam profile after the reflection on the optical surfaces with periodic structures. Herein, a generalized equation, which determines the period of the constructive interference formed by Bragg scattering, is presented for the only two diffracted beam modes given by the mth and nth order. Two theoretical calculations, one being an analytical calculation based on the interference equation, and the other being a numerical simulation based on Fourier optics, are conducted for all the diffracted beam modes to reflect the effects of higher-order diffraction. Furthermore, the simulation results based on the Fourier optics are much closer to real phenomena because the boundary conditions are exactly considered. As the aspect ratio of the periodic structure on the optical surface increases, the period of constructive interference decreases, and its intensity is remarkably increased from the two theoretical calculations. Our results will be extensively applied as a novel theoretical tool to analyze quantitatively the effects of periodic structures on the propagating beam profile by providing a deep understanding about the interference formed by Bragg scattering.

In this work, a coplanar waveguide employing chemically modified graphene was fabricated on a polyethylene terephthalate (PET) substrate and its RF loss characteristics were investigated. According to the results, the coplanar waveguide showed much lower loss characteristics than conventional graphene-based transmission line. The insertion loss of conventional graphene/Si structure was – 24 to − 33 dB at 1 GHz, but that of the graphene/PET structure was − 0.773 dB at the same frequency. However, the graphene/PET structure showed a comparatively higher loss than the gold–Ti/PES structure. The higher loss of the graphene/PET structure originated from the comparatively lower conductivity of graphene. The results of the present study indicate that the graphene/PET structure is prospective for application in flexible RF devices.

Effects of dietary inclusion of yacon, Polymnia sonchifolia (YC), ginger, Zingiber officinale (GG), and blueberry, Vaccinium ashei (BB), on growth, body composition and challenge test of rockfish against Edwardsiella tarda compared to ethoxyquin were investigated. Three hundred and sixty fish were randomly distributed into 12 flow-through tanks. Four experimental diets were prepared: the control diet (Con) with 0.1 g/kg ethoxyquin, and YC, GG and BB diets. Each diet was assigned to triplicate tanks of fish and hand-fed for 8 weeks. Externally normal fish after fourth and eighth weeks of feeding trial were infected with Edwardsiella tarda for challenge test. Weight gain and specific growth rate (SGR) of fish fed the YC diet were greater than those of fish fed all other diets. Feed efficiency, protein efficiency ratio and protein retention of fish fed the YC diet were higher than those of fish fed all other diets. In the both fourth and eighth weeks of infection trials, mortality of fish fed the Con diet was higher than that of fish fed all other diets. In conclusion, dietary inclusion of YC, GG and BB increased weight gain and SGR of fish. YC, GG and BB for 4 and 8 weeks lowered mortality of fish at occurrence of E. tarda.

Substitution effect of sea tangle (ST) with tunic of sea squirt (SS) in diet on growth and carcass composition of juvenile abalone was determined. One thousand four hundred and seventy abalones were distributed into 21 containers. Six formulated diets in triplicate were prepared. A 200 g/kg ST was included into the ST0 diet. The 200, 400, 600, 800 and 1000 g/kg of ST were substituted with the same amount of tunic of SS, referred to as the ST200, ST400, ST600, ST800 and ST1000 diets, respectively. Finally, Undaria was prepared to compare effect of the formulated diets on performance of abalone. The experimental diets were fed to abalone for 16 weeks. Weight gain of abalone fed the ST400 diet was higher than that of abalone fed the ST0, ST600, ST800 and ST1000 diets and Undaria. Weight gain of abalone fed the formulated diets was higher than that of abalone fed the Undaria. The chemical composition of the carcass of abalone was affected by dietary substitution of ST with tunic of SS. In conclusion, ST could be completely substituted with tunic of SS without retardation in performance of abalone. Abalone fed the ST400 diet substituting 400 g/kg ST with tunic of SS achieved the best growth.

Thin films of SrRuO3, which is a conductive oxide, have the potential for use as electrode layers in versatile electronic applications, particularly with perovskite structured dielectric and ferroelectric oxide thin films. Moreover, for practical device applications, it is important to develop the deposition process of low-resistivity SrRuO3 thin films on SiO2 substrates. Therefore, in this study, the growth and characteristics of SrRuO3 thin films deposited by radiofrequency magnetron sputtering on SiO2 substrates without a buffer layer were investigated. It was found that the oxygen flow ratio in the growth ambient, post-deposition annealing temperature, and post-deposition annealing time are key parameters in realizing high-quality SrRuO3 thin films. When SrRuO3 thin films were deposited with a gas flow ratio of Ar:O2 = 1:1.5 and subjected to post-deposition annealing in an oxygen ambient at 750 °C for 3 min, they exhibited an excellent resistivity of 148 μΩ-cm. This value is comparable to that of SrRuO3 thin films epitaxially grown on single-crystal SrTiO3 or LaAlO3 substrates.

We successfully deposited hexagonal wurtzite Mg x Zn1−x O (0 ≤ x ≤ 0.18) films on Si substrates by using RF magnetron co-sputtering with ZnO and Mg0.3Zn0.7O targets. The Mg content was varied by controlling the RF power of the Mg0.3Zn0.7O target while the RF power of the ZnO target was fixed at 100 W. The electrical properties of the Mg x Zn1−x O films were investigated by using a transmission line model (TLM) with Ti/Au electrode and Hall effect measurements. The X-ray diffraction (XRD) results demonstrate that some Zn atoms can be replaced by Mg atoms in the Mg x Zn1−x O films. As the Mg content was increased from 0 at.% to 18 at.%, the resistivity of Mg x Zn1−x O films increased and the carrier concentration decreased from 1.17 × 1019 cm−3 to 1.17 × 1017 cm−3, which indicates a decrease in the number of oxygen vacancies. Meanwhile, the Hall mobility increased to 15.3 cm2/Vs. The electrical properties of Mg x Zn1−x O films were tuned by using the Mg content.

In general, growing ZnO nanorods with the hydrothermal method requires the deposition of ZnO buffer layers. This is the most essential step, because the morphology of ZnO nanorods is strongly influenced by the buffer layer on a flexible substrate. In this work, we study the effect of the buffer layer when ZnO nanorods are grown. ZnO nanorods were grown on ZnO-buffered PES substrates with the hydrothermal method. As a result, it was found that the ZnO buffer layer using PLD had excellent characteristics compared with the ZnO buffer layer using sputtering.

In laser-plasma interactions (LPI), the laser beam mode is a critical parameter when trying to explore new physical phenomena. Of the various spatial beam modes, the Laguerre-Gaussian (LG) mode with vortex phase has attracted considerable attention due to its unique features, including the ability to carry an orbital angular momentum. Due to this, it has been actively applied to LPI, which mainly utilize ultrashort intense laser pulses. However, existing transmissive phase-manipulating optical elements have several limitations when applied in LPI due to critical issues such as pulse broadening, attenuation, and beam shape–all of which have an influence on the beam quality, as well as, geometry, size, simplicity, and cost–all of which are related to processing technologies. In this paper, we present a series of procedures to obtain high-quality low-order (l = 1 and 2) LG vortex beams from large-sized off-axis reflective spiral phase plates (ORSPPs). The geometric designs for various surface structures, electromagnetic wave simulations in the extra-large domain, hybrid-mechanical processing technique attempted newly, and experimental demonstrations are involved. Experimental observations of LG intensity distributions and interference fringes were verified with the simulation results of Poynting vector, phase, and angular momentum densities. The beam quality of LG intensity distributions was analyzed quantitatively through the investigation of an annular zone formed from the uniformity of the stepped and continuous surface structures of ORSPPs. Furthermore, we numerically investigated the physical phenomena on the high-intensity angular momentum transfer from light to matter, considering ORSPP–driven low-order LG vortex laser pulses, by performing 3D particle-in-cell simulations.

A double layered plasmonic device based on transferring technique with polystyrene nano-beads is analyzed and demonstrated to increase the sensing characteristics of plasmonic sensor system. The double layered plasmonic devices are calculated using the three-dimensional finite-difference time-domain method for the width and thickness of the nano-hole structures. The double layered plasmonic devices with different diameters of the Au nano-hole are fabricated by transferring method with commercially available chloromethyl latex with a diameter of 0.42 μm. The optimum sensing characteristic of the proposed plasmonic device is obtained with the film and the hole thickness of 15 and 15 nm in the 246 nm wide nano-hole size. The best sensitivity of the proposed plasmonic sensor is 67.7 degree/RIU when the sensitivity of the conventional plasmonic sensor is 42.2 degree/RIU.

In this paper, we demonstrate the electrical properties, depending on grain size, of nanocrystalline indium tin oxide (ITO) thin films prepared with a solution process. The size distributions of nanometer-sized ITO film grains increased as the post-annealing temperature increased after deposition; the grain sizes were comparable with the calculated electron mean free path. The mobility of ITO thin films increased with increasing grain size; this phenomenon was explained by adopting the charge-trapping model for grain boundary scattering. These findings suggest that it is possible to improve mobility by reducing the number of trapping sites at the grain boundary.

A polycrystalline MgZnO/ZnO bi-layer was deposited by using a RF co-magnetron sputtering method and the MgZnO/ZnO bi-layer TFTs were fabricated on the thermally oxidized silicon substrate. The performances with varying the thickness of ZnO layer were investigated. In this result, the MgZnO/ZnO bi-layer TFTs which the content of Mg is about 2.5 at % have shown the enhancement characteristics of high mobility (6.77–7.56 cm 2 V −1 s −1 ) and low sub-threshold swing (0.57–0.69 V decade −1 ) compare of the ZnO single layer TFT ( μ FE = 5.38 cm 2 V −1 s −1 ; S.S. = 0.86 V decade −1 ). Moreover, in the results of the positive bias stress, the ΔV on shift (4.8 V) of MgZnO/ZnO bi-layer is the 2 V lower than ZnO single layer TFT (ΔV on = 6.1 V). It reveals that the stability of the MgZnO/ZnO bi-layer TFT enhanced compared to that of the ZnO single layer TFT.

We directly observed the crystal structure changes of the MgxZn1 − xO alloy thin film deposited on Si (111) substrates. Through the in situ heating transmission electron microscopy study, it was determined that the crystal structure changes did not occur up to at 400 °C, whereas the disappearance of the hexagonal structure was observed at 500 °C in the layer of nanosized grains. Additionally, the decreased intensity of the Zn L-edge was analyzed in the comparison of the core loss electron energy loss spectroscopy spectra of the Zn L-edge and the Mg K-edge obtained at room temperature and 500 °C. Based on these experimental results, the process of crystal structure changes could be explained by the evaporation of Zn atoms in the MgxZn1 − xO alloy system. This phenomenon is prominent in the improvement of the microstructure of the MgxZn1 − xO alloy thin film by controlling the thermal annealing temperature.

an open stub employing a fishbone-type transmission line (OSFTTL) was fabricated on PES, and its characteristics were investigated. The OSFTTL showed much higher capacitance values than the OSCPW due to the high effective permittivity value. Specifically, the OSFTTL on PES showed capacitance values of 0.066 ~ 0.24 pF from 0.5 to 50 GHz, which are higher than those for the open stub on silicon substrate. The above results indicate that the OSCPW and OSFTTL on PES can be effectively used for application to low/high-value capacitive matching components on microwave and millimeter wave flexible MMIC. To the best of the authors' knowledge, this work is the first report of the investigation of RF capacitive matching components on PES substrate.

In particular, the PES substrate, the crystal structure of the amorphous as well as the surface morphology is not good. So research of thin films growth for epitaxial growth by the use of a buffer layer on the amorphous PES substrate is essential. Therefore, in this study, we deposited ZnO thin-film on PES substrate, and grown ZnO nanorods at various ZnO concentrations during 1 hour. We used SEM, XRD, and HP 4145B for observe the structural and electrical characteristics of ZnO nanorods. UV-visible spectrometer was used to get the band gap and transmittance.

In this work, a fishbone-type transmission line employing a comb-type ground plane (FTLCGP) was fabricated on polyethersulfone (PES) substrate, and its RF characteristics were thoroughly investigated. According to the results, it was found that the FTLCGP on PES showed periodic capacitance values much higher than other types of transmission lines due to a coupling capacitance between the signal line and ground, which resulted in a reduction of wavelength and line width. Using the theoretical analysis, we also extracted the bandwidth characteristic of the FTLCGP on PES. According to the result, the FTLCGP structure showed a cut-off frequency of 280 GHz.

In this study, a half-circled cavity based microdisk laser diode is proposed and demonstrated experimentally for an integrated photonic biochemical sensor. Conventional microdisk sensors have limitations in optical coupling and reproducibility. In order to overcome these drawbacks, we design a novel half-circled micro disk laser (HC-MDL) which is easy to manufacture and has optical output directionality. The Q-factor of the fabricated HC-MDL was measured as 7.72 × 106 using the self-heterodyne method and the side mode suppression ratio was measured as 23 dB. Moreover, gas sensing experiments were performed using the HC-MDL sensor. A wavelength shift response of 14.21 pm was obtained for 100 ppb dimethyl methylphosphonate (DMMP) gas and that of 14.70 pm was obtained for 1 ppm ethanol gas. These results indicate the possibility of highly sensitive gas detection at ppb levels using HC-MDL. This attractive feature of the HC-MDL sensor is believed to be very useful for a wide variety of optical biochemical sensor applications.

We demonstrated group velocity delay using a metal–insulator–metal structure for slow light that would be very simple to fabricate. A negative Goos–Hanchen shift of the surface plasmon resonance can be caused by incident radiation while reflecting, resulting in a general group delay. Using this phenomenon, we induced a group delay of 70 fs using a very simple 20-μm-long waveguide.

The effect of the substitution of fishmeal with tuna by-product meal (TBM) in the diet of Korean rockfish on growth, body composition, plasma chemistry and amino acid profiles was determined. Nine experimental diets were prepared. The control (Con) diet consisted of 550 g kg−1 fishmeal. The 10, 20, 30, 40, 60, 80 and 100 % fishmeal diets were substituted with tuna by-product meal (TBM), referred to as the TBM10, TBM20, TBM30, TBM40, TBM60, TBM80 and TBM100 diets, respectively. Finally, the fishmeal and soybean meal was completely replaced with TBM in the diet TBM100-S. There was no significant difference in weight gain and SGR of the fish that were fed the TBM40 and Con diets. The feed conversion ratio (FCR) of the fish that were fed the Con, TBM10, TBM20 and TBM30 diets was lower than that of the fish that were fed all of the other diets. The protein efficiency ratio (PER) of fish that were fed the TBM10, TBM20 and TBM300 diets was higher than that of fish that were fed the TBM40, TBM60, TBM80, TBM100 and TBM100-S diets. It can be concluded that the substitution of fishmeal with up to 40 and 30 % TBM in the diet of juvenile Korean rockfish could be made without exerting a detrimental effect on their growth (SGR) and feed utilization (FCR and PER), respectively.

We have investigated the electric-field intensity distributions and characteristics of the whispering-gallery mode (WGM) from a planar microdisk using a three-dimensional finite-difference time-domain method. Silicon nitride (Si 3 N 4 ) planar microdisks on silica (SiO 2 ) substrates have been systematically analyzed considering the effects of the sidewall angle, etching depth, and height. Superpositioning of the TE and TM modes which is caused by the skew effect according to the sidewall angle has been demonstrated. Furthermore, the mode splitting caused by the change from single mode to multi-mode regimes due to an increase in the height has been analyzed. Several planar microdisks of Si 3 N 4 on SiO 2 were fabricated, and their resonance characteristics were probed by using micro-photoluminescence spectroscopy. A quality factor of 5×10 3 for microdisks with a diameter of 3.5 μm and sidewall angle of 35° was observed in the visible range. The WGMs of fabricated microdisk were analyzed according to the details of the model and found to be in good agreement

A ZnO thin-film transistor (TFT) with an MgO insulator was fabricated on a silicon (100) substrate using a radiofrequency magnetron sputtering system. The MgO insulator was deposited using the same deposition system; the total pressure during the deposition process was maintained at 5 mTorr, and the oxygen percentage of O2/(Ar + O2) was set at 30%, 50%, or 70%. The process temperature was maintained at below 300 °C. The dielectric constant of the MgO thin layer was approximately 11.35 with an oxygen percentage of 70%. This ZnO TFT displayed enhanced transistor properties, with a field-effect mobility of 0.0235 cm2 V−1 s−1, an ION/IOFF ratio of ∼105, and an SS value of 1.18 V decade−1; these properties were superior to those measured for the MgO insulators synthesized using oxygen percentages of 30% and 50%.

Laboratory for Electromagnetic Field and Microwave Electronics, ETH Zurich, Zurich 8092, Switzerland(Received January 23, 2014; Revised February 3, 2014; Accepted February 19, 2014)Abstract: We have investigated the optical properties of plamonic waveguide with tapered structure based on InP material for photonic integrated circuit(PIC). The proposed plasmonic waveguide is covered with the Ag thin film to generate the plasmonic wave on metallic interface. The optical characteristics of plasmonic waveguide were calculated using the three-dimensional finite-difference time-domain method. The plasmonic waveguide was fabricated with the lengths of 2 to 10 μm and the widths of 400 to 700 nm, respectively. The plasmonic mode and optical loss were measured. The optimum plasmonic length is 10 μm and widths are 600 and 700 nm in the fabricated waveguide. This plasmonic waveguide can be directly integrated with other conventional optical devices and can be essential building blocks of PIC. Keywords: FDTDSurface plasmon resonance, Plamonic waveguide, Tapered structure, PIC

In this work, the coplanar waveguide is fabricated on a PES (poly[ether sulfone]) substrate for application to a flexible monolithic microwave integrated circuit, and its RF characteristics were thoroughly investigated. The quality factor of the coplanar waveguide on PES is 40.3 at a resonance frequency of 46.7 GHz. A fishbone-type transmission line (FTTL) structure is also fabricated on the PES substrate, and its RF characteristics are investigated. The wavelength of the FTTL on PES is 5.11 mm at 20 GHz, which is 55% of the conventional coplanar waveguide on PES. Using the FTTL, an impedance transformer is fabricated on PES. The size of the impedance transformer is , which is 69.2% of the size of the transformer fabricated by the conventional coplanar waveguide on PES. The impedance transformer showed return loss values better than -12.9 dB from 5 GHz to 50 GHz and an insertion loss better than -1.13 dB in the same frequency range.

We demonstrate significant enhancement of an effective Q-factor in a silica planar waveguide-based asymmetric Mach–Zehnder interferometer (AMZI) coupled with a microdisk. To enhance the Q-factor, which is required to more effectively measure the signal changes occurring during biochemical events, the structure utilizes resonance mode splitting. This phenomenon is observed through power cancellation at the same amplitude and a 180° phase difference of each path in the AMZI. In this study, we experimentally showed the effective Q-factor enhancement by comparing resonance characteristics of a fabricated microdisk, AMZI, and the proposed structure at equal fabrication conditions. We measured an effective Q-factor of 9.15 × 104 with a 22 dB extinction ratio.

The periodic structure on the optical surface affects the beam shape and its propagation. As the size of the optical elements becomes larger and its shape becomes complicated, the quantitative analysis of the effect of the periodic structure on the optical surface becomes indispensable given that it is very difficult to completely eliminate the microscopic periodic structures. Herein, we have experimentally investigated Bragg scattering from an optical surface with extremely small aspect ratios (~10−5) and groove densities (0.5 lines/mm). We observed the period of the constructive interference formed due to the propagation of the 0th, 1st, and −1st beam modes caused by Bragg scattering. When the periodic structure has a modulation depth of ± 50 nm, the intensity increase of constructive interference between the beam modes formed by Bragg scattering was > 10 times greater than the intensity of a flat surface at the propagation distance at which constructive interference was most pronounced. This study is envisaged to open new avenues for the quantification of the effect of periodic structures based on the observation of the interference on the beam profile formed by Bragg scattering during the beam propagation.

Concern for the TOS (Transparent Oxide Semiconductor) is increasing with the recent increase in interest for flexible device. Especially MgZnO has attracted a lot of attention. , which ZnO-based wideband-gap alloys is tuneable the band-gap ranges from 3.36 eV to 7.8 eV. In particular, the flexible substrate, the crystal structure of the amorphous as well as the surface morphology is not good. So research of MgZnO thin films growth on flexible substrate is essential. Therefore, in this study, we studied on the effects of the oxygen partial pressure on the structural and crystalline of thin films. MgZnO thin films were deposited on PES substrate by using pulsed laser deposition. We used XRD and AFM in order to observe the structural characteristics of MgZnO thin films. UV-visible spectrophotometer was used to get the band gap and transmittance. Crystallization was done at a low oxygen partial pressure. The crystallinity of MgZnO thin films with increasing temperature was improved, Grain size and RMS of the films were increased. MgZnO thin films showed high transmittance over 80% in the visible region.

We investigated the changes in the preferred orientation and microstructure of ZnO:In films with increasing In content. ZnO and ZnO:In films with In contents of up to 50 at.% were deposited on Si (111) substrates by using pulsed laser deposition and were subsequently characterized using X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The structural analysis of the films revealed that as the In content was increased, the preferred orientation of the films changed from a c-axis to a random orientation at In content of 10 at.% and finally became a a-axis orientation at In content of 20 at.%. The column grain size and values of root-mean-square (RMS) roughness showed a gradual decrease with increasing In content. As the In content was increased to 10 at.%, the initial orientation of the nuclei changed from a c-axis to a random orientation; nuclei with a preferred an a-axis orientation were dominant for an In content of 20 at.%, reflecting a deterioration in the tetrahedral coordination of ZnO. Consequently, the growth direction of the grains changed, and the preferred orientation of the grains affected the microstructure.

We investigated the incorporation of Ga into zinc-tin-oxide (ZTO) thin-film transistors (TFTs) and assessed the TFTs’ electrical and stability properties. The Ga-doped ZTO (ZTO:Ga) thin films were deposited on thermally oxidized silicon substrates by using a sol-gel technique. The Ga contents were varied from 1 to 20 atomic percent (at.%) while the Zn:Sn ratio was maintained at 1:1. The dependence of the ZTO:Ga thin films’ structural properties on the Ga content was analyzed using Xray diffraction (XRD) spectra, scanning probe microscopy (SPM), X-ray photoelectron spectroscopy (XPS), and UV-visible spectrophotometry. The field effect mobilities and the I on /I off ratios of the ZTO:Ga-TFTs were between 0.68 and 2.95 cm2Vs−1s−1 and ∼104 and ∼106, respectively. At low Ga contents, the (

We fabricated a series of ZnO-based thin-film transistors (TFTs) in which the Mg composition ratio in the active layer was varied by controlling the RF power applied to the ZnO and the Mg0.3Zn0.7O targets. Mg x Zn1−x O alloy films were deposited by RF co-sputtering onto a SiO2/n+-Si substrate at 300 °C. The Mg content in each ZnO film was measured and the band gaps were found to increase from 3.27 to 3.93 eV with increasing Mg content. The field effect mobility and the on/off ratio were decreased from 9.12 cm2V−1s−1 and 109 to 3.11 cm2V−1s−1 and 108, respectively, as Mg incorporation was increased. We report the feasibility of Mg incorporation by using a cosputtering technique, and the electrical and the structural properties of the TFT ZnO active layer as a function of Mg content are discussed.

The effect of sputtering condition on the structural properties of ZnO thin films grown by RF magnetron sputtering system was investigated for TFT driver circuit. ZnO thin films were grown with ZnO target varying RF power and working pressure. Structural properties were investigated by X-ray dif-fraction (XRD) and atomic force microscope (AFM). The ZnO thin films have sufficient crystallinity on the 100W RF power. But, the surface roughness of ZnO films was increased as increased RF power. As increased working pressure from 5 mTorr to 15 mTorr, a full width at half maximum (FWHM) of ZnO (002) peak was increased. Keywords: Thin film transistor, Thin film, Oxide semiconductor, Grain size, Atomic Force Microscopy 1. 서 론 최근 선박의 평형을 유지하기 위해 선박에 유입되는 선박평형수(Ballast water)의 처리방법에 소비전력이 적은 자외선 발광 다이오드(UV LED)를 적용하려는 시도가 이루어지고 있다[1]. UV LED 는 AlN 기반의 재료를 사용하여야 하나 격자부정합으로 인한 발광효율이 저하, 온도 민감성, 높은 Al 농도에서의 낮은 성장률 등으로 AlGaN/GaN계를 이용한 UV LED는 제작에 많은 어려움이 있다[2]. 또한 기존의 디스플레이를 대체할 수 있는 투명하고 유연한 특성을 가지는 차세대 투명 플렉시블 디스플레이(transparent flexible display)에 대한 연구가 국내외에서 활발히 진행되고 있다. 플렉시블 디스플레이의 active matrix를 위한 구동소자는 수소화된 비정질 실리콘을 채널 물질로 사용한 박막트랜지스터(hydrogenated amorphous silicon thin film transistor, a-Si:H TFT)가 증착공정이 간단하고 공정비용이 적게들어 주로 사용되고 있다[3].

Effects of dietary Scutellaria baicalensis extract (SBE) on growth, feed utilization and challenge test of olive flounder (Paralichthys olivaceus) were determined. Six hundred thirty fish averaging 5.0 g were distributed into 18, 180-L tanks. Six experimental diets were prepared in triplicate: SBE-0, SBE-0.5, SBE-1, SBE-2, SBE-3 and SBE-5 diets containing SBE at the concentrations of 0, 0.5, 1, 2, 3 and 5%, respectively. Fish were hand-fed to apparent satiation twice a day for 8 wks. At the end of 8-wk feeding trial, ten fish from each tank were infected by Edwardsiella tarda for challenge test. Survival and weight gain of fish were not affected by dietary concentrations of SBE. However, specific growth rate of fish fed the SBE-2 diet was higher than that of fish fed the SBE-0, SBE-1, SBE-3 and SBE-5 diets. Neither feed efficiency nor serum chemical composition of fish was affected by dietary concentrations of SBE. The cumulative mortality of fish fed the SBE-0 diet was 100% at 96 h after E. tarda infection, but 77 to 87% for fish fed the other diets. Dietary inclusion of 2% SBE appears to be recommendable to improve specific growth rate of fish and SBE had the potential to mitigate mortality of fish at E. tarda infection.