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Xiao W.-Z.,Key Laboratory for Micro Nano Optoelectronic Devices | Xiao W.-Z.,Hunan Institute of Engineering | Wang L.-L.,Key Laboratory for Micro Nano Optoelectronic Devices | Xu L.,Key Laboratory for Micro Nano Optoelectronic Devices | And 2 more authors.
Solid State Communications | Year: 2010

Based on first-principles spin-polarized density functional theory calculations, the electronic and magnetic properties of nitrogen-doped monoclinic β-phase gallium oxide are investigated. Calculations predict that the spin-polarized state is stable with a magnetic moment of about 1.0 μB per nitrogen-dopant. The magnetic moment mainly arises from the p orbital of nitrogen, with a little contribution from the Oxygen atoms surrounding it. Magnetic coupling between different nitrogen atoms is discussed, and the results show that the hole-mediated short-range p-p exchange mechanism is responsible for the predicted ferromagnetism. Calculations also reveal that experimentally observed red-shift should be N-2p gap states to band transition. Crown Copyright © 2010.


Xiao W.-Z.,Key Laboratory for Micro Nano Optoelectronic Devices | Xiao W.-Z.,Hunan Institute of Engineering | Wang L.-L.,Key Laboratory for Micro Nano Optoelectronic Devices | Xu L.,Key Laboratory for Micro Nano Optoelectronic Devices | And 2 more authors.
Solid State Communications | Year: 2010

The electronic structures and magnetic properties in Carbon-doped CeO2 have been investigated by means of first-principles calculations based on the LSDA+U scheme. The results demonstrate a magnetic moment of 2.00 μB per supercell with one Carbon dopant which mainly stems from Hund's rule coupling based on rather localized 2p, 5d and 4f states. The hole-mediated long-range magnetic coupling between local magnetic moments can be attributed to the collective effects of the p-p, p-d, and p-f hybridizations between C and neighboring O or Ce atoms. Ferromagnetism and half-metallic characteristics of C-doped CeO2 make it possible to be an ideal material for spintronic devices. Crown Copyright © 2010.


Xu C.,Key Laboratory for Micro Nano Optoelectronic Devices | Xu C.,Hunan University | Yang D.,Hunan University | Mei L.,Key Laboratory for Micro Nano Optoelectronic Devices | And 10 more authors.
ACS Applied Materials and Interfaces | Year: 2013

Surface modification of inorganic nanoparticles (NPs) is extremely necessary for biomedical applications. However, the processes of conjugating ligands to NPs surface are complicated with low yield. In this study, a hydrophilic shell with excellent biocompatibility was successfully constructed on individual gold NPs or gold nanorods (NRs) by encapsulating NPs or NRs in graphene oxide (GO) nanosheets through electrostatic self-assembly. This versatile and facile approach remarkably decreased the cytotoxicity of gold NPs or NRs capping with surfactant cetyltrimethylammonium bromide (CTAB) and provided abundant functional groups on NPs surface for further linkage of polyethylenimine (PEI). The PEI-functionalized GO-encapsulating gold NPs (GOPEI-AuNPs) were applied to delivery DNA into HeLa cells as a novel gene vector. It exhibited high transfection efficiency of 65% while retaining 90% viability of HeLa cells. The efficiency was comparable to commercialized PEI 25 kDa with the cytotoxicity much less than PEI. Moreover, the results on transfection efficiency was higher than PEI-functionalized GO, which can be attributed to the small size of NPs/DNA complex (150 nm at the optimal w/w ratio) and the spherical structure facilitating the cellular uptake. Our work paves the way for future studies focusing on GO-encapsulating, NP-based nanovectors. © 2013 American Chemical Society.


Zhu X.M.,Key Laboratory for Micro Nano Optoelectronic Devices | Zhu X.M.,Hunan University | Xu M.,Key Laboratory for Micro Nano Optoelectronic Devices | Xu M.,Hunan University | Liu Q.H.,Hunan University
International Journal of Geometric Methods in Modern Physics | Year: 2010

It is demonstrated that the Cartesian momenta and positions offer a proper description for the motion of particles constrained on the surface of a sphere. In classical limit, their mean values on the classical wave packet go over to classical quantities. © 2010 World Scientific Publishing Company.


Liu S.,Key Laboratory for Micro Nano Optoelectronic Devices | Li L.,Key Laboratory for Micro Nano Optoelectronic Devices | Hao Q.,Key Laboratory for Micro Nano Optoelectronic Devices | Yin X.,Key Laboratory for Micro Nano Optoelectronic Devices | And 4 more authors.
Talanta | Year: 2010

A novel non-enzymatic hydrogen peroxide sensor was realized from Mn-nitrilotriacetate acid (Mn-NTA) nanowires, which were successfully fabricated via a facile hydrothermal route. Cyclic voltammetry (CV) revealed that the Mn-NTA nanowires exhibited direct electrocatalytic activity for the oxidation of H2O2 in phosphate buffer solution. The sensor showed linear response to H2O2 at the concentrations range from 5 × 10-6 M to 2.5 × 10-3 M with a detection limit of 2 × 10-7 M. The sensitivity was up to 78.9 μA mM-1 cm-2. These results indicated that the Mn-NTA nanowires were promising in realizing non-enzymatic H2O2 detection. © 2010 Elsevier B.V. All rights reserved.


Li L.M.,Key Laboratory for Micro Nano Optoelectronic Devices | Du Z.F.,Key Laboratory for Micro Nano Optoelectronic Devices | Wang T.H.,Key Laboratory for Micro Nano Optoelectronic Devices
Sensors and Actuators, B: Chemical | Year: 2010

We report the synthesis of Al-doped ZnO nanotetrapods and investigate the effects on their sensing properties. It is found that Al doping introduces more defects based on the results of Raman and photoluminescence experiments and further confirmed by the sensing experiments. The green emission is enhanced and the relative intensity ratio between the green emission and the ultraviolet emission increases for Al-doped ZnO nanotetrapods. The ethanol sensing properties of ZnO nanotetrapods are effectively improved by Al doping. These can be explained in terms of the enhanced modulation of conductance caused by the preferential adsorption of the ethoxy on the oxygen vacancies. Our results provide an approach to exploit the improvement of gas sensitivity of ZnO nanomaterials. © 2010 Elsevier B.V. All rights reserved.


Liu S.,Key Laboratory for Micro Nano Optoelectronic Devices | Yin X.,Key Laboratory for Micro Nano Optoelectronic Devices | Chen L.,Key Laboratory for Micro Nano Optoelectronic Devices | Li Q.,Key Laboratory for Micro Nano Optoelectronic Devices | Wang T.,Key Laboratory for Micro Nano Optoelectronic Devices
Solid State Sciences | Year: 2010

In this work, we reported a facile ethanol solvothermal approach to fabricate highly dispersive 3D flowerlike SnS2 architectures. The effects of synthetic conditions, such as the solvent system and the concentration of thiourea, on the morphology of the products were investigated. A possible growth mechanism for the formation of 3D flowerlike architectures was preliminarily propounded on the basis of the evolution of the structure and the morphology with increasing the reaction time. As anode materials of rechargeable Li-ion batteries, the as-prepared flowerlike SnS2 structures exhibited exceptional good electrochemical properties, which revealed a higher reversible capacity about 502 mA h g-1 and more stable cyclic retention at 50th cycle than the as-prepared SnS2 nanoplates. The reasons for the improved electrochemical performance of the flowerlike structures have been proposed. All the results demonstrated that they were potential anode materials in Li-ion batteries. © 2010 Elsevier Masson SAS. All rights reserved.


Fan Z.-Q.,Key Laboratory for Micro Nano Optoelectronic Devices | Chen K.-Q.,Key Laboratory for Micro Nano Optoelectronic Devices
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2010

By applying first-principles quantum transport calculations, we investigate the transport properties of the oligo(p-phenylenevinylene)s molecular devices modulated with different side groups. The calculated results show that for the system modulated with - NH2, the highest occupied molecular orbital is localized, while for the system modulated with - NO2, the lowest unoccupied molecular orbital is localized. The electron transport will be enhanced when modulated only with - NH2 or - NO2, but will be weakened when modulated with both - NH2 and - NO2. Negative differential resistance is observed in the system modulated with two - NH2. A mechanism for the negative differential resistance behavior is suggested. © 2009.


Peng X.-F.,Key Laboratory for Micro Nano Optoelectronic Devices | Chen K.-Q.,Key Laboratory for Micro Nano Optoelectronic Devices
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2010

Ballistic thermal transport properties at low temperatures in a quantum wire modulated with two coupling quantum dots are studied. The results show that when the temperature is low enough, the reduced thermal conductance displays monotonic behavior with the change of structural parameters; while at higher temperature, the reduced thermal conductance displays a nonlinear behavior. It is found that the phonon transmission and thermal conductance sensitively depend on the relative position of quantum dots and symmetric axis of the quantum wire. When the symmetry axis of quantum wire is away from the center of the quantum dots, the thermal conductance increases monotonously. It is also found that the thermal conductance can be modulated by the magnitude of the quantum dots and the length between the two quantum dots. Moreover, inhomogeneous quantum transport steps and quantized thermal conductance plateau can be observed in such structure. © 2010 Elsevier B.V. All rights reserved.


Zhang H.Z.,CAS Ningbo Institute of Material Technology and Engineering | Cao H.T.,CAS Ningbo Institute of Material Technology and Engineering | Chen A.H.,CAS Ningbo Institute of Material Technology and Engineering | Liang L.Y.,CAS Ningbo Institute of Material Technology and Engineering | And 3 more authors.
Solid-State Electronics | Year: 2010

We report on the fabrication of bottom-gate thin-film transistors (TFTs) using indium-oxide (In2O3) thin films as active channel layers. The films were deposited on thermally grown silicon dioxide (SiO2)/n-type silicon (Si) at room temperature (RT) by radio-frequency (RF) magnetron sputtering. The effect of deposition pressure on the performance of In2O3-TFTs was investigated in detail. A significant improvement of the device performance was observed for In2O3-TFTs with the decrease of the working pressure, which is attributed to enhanced densification, better surface morphology of the In2O3 channel layers prepared at lower deposition pressure. The fabricated TFT with optimal device performance exhibited a field-effect mobility (μFE) of 31.6 cm2 V-1 s-1, a drain current on/off ratio of ∼107, a low off drain current of about 10-10 A and a threshold voltage of 7.8 V. Good device performance and low processing temperature make the In2O3-TFTs suitable for the potential applications in the transparent electronics. © 2009 Elsevier Ltd. All rights reserved.

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