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Li E.,Xian University of Science and Technology | Li E.,Institute for Superconducting and Electronic Materials ISEM | Wu G.,Xian University of Science and Technology | Cui Z.,Xian University of Science and Technology | And 3 more authors.
Nanotechnology | Year: 2016

Pure and Se-doped GaN nanowires (NWs) are synthesized on Pt-coated Si(111) substrates via chemical vapor deposition. The GaN NWs exhibit a uniform density with an average diameter of 20-120 nm. The structure of the NWs is wurtzite hexagonal, and the growth direction is along [0001]. Field emission measurements show that the Se-doped GaN NWs possess a low turn-on field (2.9 V μm-1) compared with the pure GaN NWs (7.0 V μm-1). In addition, density functional theory calculations indicate that the donor states near the Fermi level are mainly formed through the hybridization between Se 4p and N 2p orbitals and that the Fermi level move towards the vacuum level. Consequently, the work functions of Se-doped GaN NWs are lower than those of pure GaN NWs. © 2016 IOP Publishing Ltd.


Feng H.,Institute for Superconducting and Electronic Materials ISEM | Feng H.,University of Wollongong | Feng H.,Beihang University | Xu Z.,Institute for Superconducting and Electronic Materials ISEM | And 17 more authors.
ACS Applied Materials and Interfaces | Year: 2015

BiOBr nanosheets with highly reactive {001} facets exposed were selectively synthesized by a facile hydrothermal method. The inner strain in the BiOBr nanosheets has been tuned continuously by the pH value. The photocatalytic performance of BiOBr in dye degradation can be manipulated by the strain effect. The low-strain BiOBr nanosheets show improved photocatalytic activity. Density functional calculations suggest that strain can modify the band structure and symmetry in BiOBr. The enhanced photocatalytic activity in low-strain BiOBr nanosheets is due to improved charge separation attributable to a highly dispersive band structure with an indirect band gap. © 2015 American Chemical Society.


Du Y.,Institute for Superconducting and Electronic Materials ISEM | Cheng Z.,Institute for Superconducting and Electronic Materials ISEM | Dou S.,Institute for Superconducting and Electronic Materials ISEM | Wang X.,Institute for Superconducting and Electronic Materials ISEM
Journal of Nanoscience and Nanotechnology | Year: 2011

Bi 2Fe 4O 9 nano and micron powders have been synthesized by a hydrothermal method. The as-obtained samples are pure phase and crystallize in the orthorhombic structure. Diverse particle morphologies, including nanoplates, nanospheres, microcubes, and microcylinders, are obtained under different synthesis conditions. The solvent N, N-Dimethylformamide (DMF), together with the mineralisers NaOH and NH 4OH, are found to be the key factors for the formation of the particles with their diverse morphologies and sizes. The magnetization dependence of temperature (M-T), observed in a field of 1000 Oe from 10 to 340 K, and M-H loops measured at 10 K indicate that the Bi 2Fe 4O 9 particles are paramagnetic at room temperature and undergo an antiferromagnetic transition at a Néel temperature (T N) of 250 K. © 2011 American Scientific Publishers.


Masilamani N.,Institute for Superconducting and Electronic Materials ISEM | Shcherbakova O.V.,Institute for Superconducting and Electronic Materials ISEM | Fedoseev S.A.,Institute for Superconducting and Electronic Materials ISEM | Pan A.V.,Institute for Superconducting and Electronic Materials ISEM | Dou S.X.,Institute for Superconducting and Electronic Materials ISEM
IEEE Transactions on Applied Superconductivity | Year: 2013

High-temperature superconducting thin films YBa2Cu 3O7-x) are emerging in superconducting single photon detector (SSPD) research as a novel replacement for conventional and semiconductor detectors. The major hindrance for this is the degradation of the superconducting properties of YBa2Cu3O7-x (YBCO) thin film with reduction of its lateral and longitudinal dimensions (i.e., film thickness and width of the stripe). Furthermore, the surface of the film should be smooth to enable fabrication of the SSPD device. In order to improve the quality of YBCO thin films, we exploited various buffer layers (i.e., SrTiO3, CeO2, and PrBa2Cu 3O7 ) with thickness of 30 ± 5 nm. We have also investigated the properties of (65 ± 5-nm-thick) YBCO films grown simultaneously on different substrates (i.e., SrTiO3 , LaAlO 3, MgO, and yttrium stabilized zirconia). For some substrate/buffer material combinations, the surface morphology of the YBCO film has been effectively improved. Also, there was only a small or no degradation of their critical temperature values. These structures give a precursor for further development of fabrication technology for YBCO-based SSPD devices. © 2012 IEEE.

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