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Nanocomposite films with cerium oxide (CeO2) nanoparticles as functional fillers and polystyrene (PS) as polymer matrix were prepared using solution casting method. Physical properties including both weak frequency dependence of dielectric permittivity and low dielectric loss were experimentally discovered in the CeO2/PS nanocomposite films. To improve the dielectric properties of films further, the surface of CeO2 nanoparticles was treated by H2O2 to increase the homogeneity of the nanocomposite film, which was confirmed by scanning electron microscopy (SEM) results. Furthermore, it was found that both the filler size and the filler volume fraction played a role on the dielectric properties of the nanocomposite films. [ABSTRACT FROM AUTHOR]

We investigate magnetotransport in the vicinity of the charge neutral point (CNP) in bilayer graphene at low temperatures. The CNP is found to vary with applied magnetic fields. Through measuring the transfer curves under different magnetic fields and at different temperatures, the temperature dependence of the peak resistivity at the CNP and under a fixed magnetic field is extracted. At low temperatures, it is found that the peak resistivity at the CNP increases exponentially with decreasing temperature under 14 T, which indicates the gap opening in zero-energy Landau level. The origins of such magnetic field induced insulating behavior are discussed. [ABSTRACT FROM AUTHOR]

We present the design and realization of ultra-thin chiral metasurfaces with giant broadband optical activity in the infrared wavelength. The chiral metasurfaces consisting of periodic hole arrays of complementary asymmetric split ring resonators are fabricated by femtosecond laser two-photon polymerization. Enhanced transmission with strong polarization conversion up to 97% is observed owing to the chiral surface plasmons resulting from mirror symmetry broken. The dependence of optical activity on the degree of structural asymmetry is investigated. This simple planar metasurface is expected to be useful for designing ultra-thin active devices and tailoring the polarization behavior of complex metallic nanostructures. [ABSTRACT FROM AUTHOR]

Surface emitting linearly polarized InGaN/GaN light emitting diode (LED) is demonstrated using a subwavelength metallic nanograting. The aluminum based grating with a period of 150 nm is fabricated on top of the p-contact layer in a conventional InGaN LED structure grown on (0001) oriented sapphire substrate. Polarization ratio can reach 7:1, the highest ever reported polarization ratio directly from a light emitting diode. The polarization characteristics are studied in details both experimentally and theoretically, suggesting an effective way to make polarized light emission devices. [ABSTRACT FROM AUTHOR]

We report a unique substrate for surface-enhanced raman spectroscopy (SERS) based on silver nanoparticles-embedded silicon nanowires (SiNWs). The SiNWs were prepared by thermal evaporation of SiO powder via oxide-assisted growth, oxide removed with HF, and then used to reduce silver ions to form a highly decorated Ag-embedded surface. Such modified SiNWs substrates yielded ultrahigh SERS sensitivity, which could detect 25 μl of 1×10-16M Rhodamine 6G, 1×10-16M crystal violet, and 1×10-14M nicotine in methanol solutions. An Ag-modified SiNW strand could also enable SERS detection of 25 μl of 1×10-8 mg/ml calf thymus DNA. The possible mechanisms for the ultrahigh SERS sensitivity were discussed. [ABSTRACT FROM AUTHOR]

We have fabricated well-ordered organic donor/acceptor nanojunction arrays comprising p-sexiphenyl (6P) and C60 via self-assembly of C60 on the molecular nanotemplate of 6P nanostripes on Ag(111). Our scanning tunneling microscopy measurements show that the preferential trapping of C60 triplets atop 6P single molecule leads to the formation of the C60/6P vertical nanojunctions with well-defined two-dimensional arrangement. Annealing this binary molecular superstructure at 380 K results in the insertion of C60 linear chains between the neighboring 6P nanostripes and thereby the appearance of the periodic C60/6P lateral nanojunction arrays. [ABSTRACT FROM AUTHOR]

A correction to the article "A Surface-Enhanced Raman Spectroscopy Substrate for Highly Sensitive Label-Free Immunoassay" is presented.

Nanodielectric elastomer films consisting of a silicone rubber as the matrix and conductive polyaniline nanorods (PANI-NR) as the filler were fabricated and their electro-mechanical actuation performance was investigated. The nanodielectric elastomers displayed a typical insulator-toconductor transition as the content of PANI-NR increased. The percolation threshold was observed to show a relatively low value of 5.2 vol. %, which should be mainly ascribed to the onedimensional structure of the nanorods. As the concentration of PANI-NR approached to the percolation threshold, the electro-mechanical actuation strain of the elastomer films was significantly enhanced. The actuation coefficient of nanodielectric elastomer films with only 4.0 vol.% PANI-NR loading was about 5 times higher than that of pure silicone rubber matrix. [ABSTRACT FROM AUTHOR]

Strands of aligned silicon nanowires (SiNWs) with lengths over 2 mm and diameters of 35 nm were synthesized via a two-step controlled growth. The large dimensionality made it possible to fabricate an individual strand of SiNWs into an electrode for cyclic voltammetric detection of bovine serum albumin (BSA). The strand sensor with the immense surface area and electrical conductivity of SiNWs shows the highest sensitivity and widest linear range ever reported for BSA detection. [ABSTRACT FROM AUTHOR]

A three-step graded undoped-InGaN layers embedded between the GaN last quantum barrier layer and the p-AlGaN electron blocking layer was proposed and its effect on the performance of InGaN/GaN light-emitting diodes was investigated both experimentally and theoretically. In the proposed structure, the electron leakage is found to be effectively reduced, while the hole injection efficiency is simultaneously increased significantly, hence enabling a greatly enhanced radiative recombination rate within the active region. As a result, improvements of 12.25% in the optical output power and 11.98% in the external quantum efficiency are obtained from the proposed device with the respect to the reference device. [ABSTRACT FROM AUTHOR]

The effect of n-AlGaN versus p-AlGaN electron-blocking layers (EBLs) on the performance of InGaN/GaN light-emitting diodes is studied in this work. Experimental results suggest that the n-type EBL leads to higher optical output power and external quantum efficiency, compared to the devices with p-AlGaN EBL, which is commonly used today. Numerical simulations on the carrier distribution and energy band diagram reveal that the n-AlGaN EBL is more efficient in preventing electron overflow, while not blocking the hole injection into the active region, hence leading to higher radiative recombination rate within the multiple quantum wells active region. [ABSTRACT FROM AUTHOR]

An experimental study is presented of a cold atmospheric Ar plasma jet with distinct advantages of low-working voltage and high plasma stability. To effectively improve the performance of the jet, a pair of pin electrodes with one floating in the air is applied. Variation in the applied voltage and/or the Ar gas flow causes the transition of the jet plasma from ignition, through stable plume to an unstable stage. The characteristics of the jet discharge are also studied by means of the electrical and spectroscopic diagnosis. [ABSTRACT FROM AUTHOR]

Using the terahertz time-domain spectroscopy, the complex refraction index and dielectric function of the pure 2,4,6-trinitro-1,3,5-trihydroxybenzene (TNPG) are calculated with the obtained parameters of the pure polyethylene (PE) and a mixture of TNPG and PE based on the Bruggeman effective medium theory. The theoretical investigation consistent with the experimental data in the vibration spectra of TNPG is presented in the range of 0.2–2.5 THz. The results reveal that the two absorption features identified as the fingerprint of TNPG in our studied range are mainly dominated by the intramolecular collective vibration modes. [ABSTRACT FROM AUTHOR]

Junctionless oxide-based neuron thin-film transistors with in-plane-gate structure are fabricated at room temperature by a laser scribing process. The neuron transistors are composed of a bottom indium-tin-oxide floating gate and multiples of in-plane control gates. The control gates, coupling with the floating gate, control the 'on' and 'off' of the transistor. Effective field-effect modulation of the drain current has been realized. AND logic is demonstrated on a dual in-plane gate neuron transistor. The developed laser scribing technology is highly desirable in terms of the fabrication of high performance neuron transistors with low-cost. [ABSTRACT FROM AUTHOR]