19 research outputs found

    Growth and Optical Properties of the Whole System of Li(Mn1−x_{1-x},Nix_{x})PO4_{4} (0 ≤ x ≤ 0.5) Single Crystals

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    A series of single crystals of Li(Mn1−x_{1-x},Nix_{x})PO4_{4} (x = 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08, 0.10, 0.15, 0.20, and 0.50) have been grown to large sizes up to 5 mm in diameter and 120 mm in length using the floating zone method for the first time. The comprehensive characterizations of the as-grown crystals were performed before further physical property measurements. The composition of the grown crystals was determined by energy-dispersive X-ray spectroscopy. The crystal structures were characterized by the X-ray powder diffraction method with a GSAS fitting for structural refinement, which reveals a high phase purity of the as-obtained crystals. The polarized microscopic images and Laue patterns prove the excellent quality of the single crystals. Oriented cuboids with sizes of 2.7 × 3.8 × 2.1 mm31−x3{1-x} along the a, b, and c crystalline directions were cut and polished for further anisotropic magnetic and transparent measurements. We also first proposed a new potential application in the non-linear optical (NLO) and laser generation application for LiMPO4_{4} (M = transition metal) materials. The optical and laser properties, such as the absorption spectra and the second harmonic generation (SHG), have been investigated and have furthermore confirmed the good quality of the as-grown single crystals

    The Electronic Structural and Defect-Induced Absorption Properties of a Ca2_{2}B10_{10}O14_{14}F6_{6} Crystal

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    Comprehensive ab initio electronic structure calculations were performed for a newly developed deep-ultraviolet (DUV) non-linear optical (NLO) crystal Ca2_{2}B10_{10}O14_{14}F6_{6} (CBOF) using the first principle method. Fifteen point defects including interstitial, vacancy, antisite, Frenkel, and Schottky of Ca, O, F, and B atoms in CBOF were thoroughly investigated as well as their effects on the optical absorption properties. Their formation energies and the equilibrium concentrations were also calculated by ab initio total energy calculations. The growth morphology was quantitatively analyzed using the Hartman–Perdok approach. The formation energy of interstitial F (Fi) and antisite defect OF_{F} were calculated to be approximately 0.33 eV and 0.83 eV, suggesting that they might be the dominant defects in the CBOF material. The absorption centers might be induced by the O and F vacancies (VF_{F}, VO_{O}), interstitial B and O (Oi_{i}, Bi_{i}), and the antisite defect O substitute of F (OF_{F}), which might be responsible for lowering the damage threshold of CBOF. The ionic conductivity might be increased by the Ca vacancy (Vca_{ca}), and, therefore, the laser-induced damage threshold decreases

    Fabrication of a Microfluidic System Using Micromolded Alginate Gel as a Sacrificial Material for Tissues Engineering

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    We described a sacrificial molding for the formation of microfluidic networks. In this molding, the micromolded calcium alginate (Ca-Alg) is introduced as a sacrificial template. The basis of this procedure is fabricating a micromolded Ca-Alg hydrogel and encapsulating this model within a second gel and removing it by ion-exchange to leave a microchannel in the remaining gel. This microfluidic system can readily deliver solutes into the channels and even control the transport of solutes from channels into the bulk of the gels. Furthermore, the perfused vascular channels can sustain the metabolic activity of encapsulated cells, indicating the feasibility of this microfluidic system in the field of tissue engineering

    High-sensitivity detection of chlorothalonil via terahertz metasensor

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    Given the complex pretreatment and low sensitivity of pesticide residue detection with the conventional testing method, a Terahertz metasensor consisting of the four-division ring resonator (FSRRs) was proposed and fabricated for the identification and detection of chlorothalonil. Through simulations, the theoretical sensitivity of this metasensor was found to reach 156.3 GHz /RIU (RIU, refractive index unit) under an analyte layer 1 μ m thick. Through experiments, firstly, the characteristic fingerprint spectrum of chlorothalonil in the THz band was obtained by detecting solid chlorothalonil with THz time-domain spectrum system. Then, Terahertz metasensor was used to detect the chlorothalonil solutions of different concentrations. The experimental results showed that the resonant peak of the metasensor was redshifted with the increase of chlorothalonil concentration. Compared with the detection strategy only using the characteristic fingerprint spectrum, the sensitivity of the metasensor improved 106 times, which was up to a minimum of 1 mg l ^−1 . This study indicates that the metasensor is a promising optical device for detecting the pesticide residues with a very high sensitivity

    Growth and Optical Properties of the Whole System of Li(Mn<sub>1-<em>x</em></sub>,Ni<em><sub>x</sub></em>)PO<sub>4</sub> (0 ≤ x ≤ 0.5) Single Crystals

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    A series of single crystals of Li(Mn1-x,Nix)PO4 (x = 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.08, 0.10, 0.15, 0.20, and 0.50) have been grown to large sizes up to 5 mm in diameter and 120 mm in length using the floating zone method for the first time. The comprehensive characterizations of the as-grown crystals were performed before further physical property measurements. The composition of the grown crystals was determined by energy-dispersive X-ray spectroscopy. The crystal structures were characterized by the X-ray powder diffraction method with a GSAS fitting for structural refinement, which reveals a high phase purity of the as-obtained crystals. The polarized microscopic images and Laue patterns prove the excellent quality of the single crystals. Oriented cuboids with sizes of 2.7 × 3.8 × 2.1 mm3 along the a, b, and c crystalline directions were cut and polished for further anisotropic magnetic and transparent measurements. We also first proposed a new potential application in the non-linear optical (NLO) and laser generation application for LiMPO4 (M = transition metal) materials. The optical and laser properties, such as the absorption spectra and the second harmonic generation (SHG), have been investigated and have furthermore confirmed the good quality of the as-grown single crystals

    Graphene-Assisted Electromagnetically Induced Transparency-like Terahertz Metabiosensor for Ultra-Sensitive Detection of Ovalbumin

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    Terahertz (THz) metamaterial (MM) biosensors are a potential method of biomolecule detection. However, there have been few reports on the detection of trace proteins. In this study, we designed a novel THz biosensor consisting of graphene, polyimide (PI), and electromagnetically induced transparency-like (EIT-like) MMs for the ultra-sensitive detection of ovalbumin (OVA). The doping analyte can influence the Fermi level and electrical conductivity of graphene, as well as the coupling of resonators in MMs. These changes are reflected in the magnitude, phase, and frequency changes in the transmission spectra. The biosensor achieved a high sensitivity function for OVA and reached a limit of detection (LoD) of 8.63 pg/mL. The results showed that by regulating the Fermi level of graphene between the valence band, Dirac point, and conduction band, the sensitivity and LoD of MM-based THz biosensors can be enhanced. Such biosensors have the potential to be used in the high-sensitivity detection of trace proteins in biomedical fields

    High Performance of InGaZnO TFTs Using HfxAlyOz Nanolaminates as Gate Insulators Prepared by ALD

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    In this study, HfxAlyOz nanolaminate, single-layer Al2O3, and HfO2 gate insulators were fabricated by atomic layer deposition (ALD) to successfully integrate the InGaZnO (IGZO) thin-film transistors (TFTs). Compared with single-layer HfO2-based TFTs, the HfxAlyOz-based IGZO TFTs showed a larger field-effect mobility of 10.31 cm2/Vs and a smaller subthreshold swing of 0.12 V/decade. Moreover, it showed a smaller threshold voltage shift of 0.5 V than that of HfO2-based TFTs under gate-bias stress at +5 V for 900 s due to the smooth surface. Moreover, the high dielectric HfxAlyOz nanolaminate had a larger equivalent SiO2 thinness than that of Al2O3 gate insulators, which are beneficial in applications of high-resolution display. Thus, the high mobility and high stability TFTs could be regarded as good candidates for active-matrix flat panel displays

    Frequency-tunable hybrid metamaterial terahertz logic gate with liquid crystal based on electromagnetically induced transparency

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    Terahertz logic gates will have a wide range of applications in future 6G communications. In this study, we theoretically propose a frequency-tunable all-optical terahertz logic gate composed of a silicon-metal composite metamaterial with a liquid crystal (LC) layer. Simulation results demonstrate the presence of electromagnetically induced transparency in the transmission spectrum of the device. Upon illumination, the transparency window in the transmission spectrum can be altered owing to the photoelectric effect in Si segments. The designed device can realize NOR Boolean operation based on the illumination-transmission response. More importantly, the LC layer with adjustable permittivity presents an effective method for manipulating the device’s working frequency. The influences of the LC layer’s thickness on the transparency window are also studied
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