Employing a simple and efficient method of electro-chemical anodization, ZnO nanowire films are fabricated on Zn foil, and an ultraviolet （UV） sensor prototype is formed for investigating the electronic transport through back-to-back double junctions. The UV （365 nm） responses of surface-contacted ZnO film are provided by I-V measurement, along with the current evolution process by on/off of UV illumination. In this paper, the back-to-back metal-seconductor-metal （M-S-M） model is used to explain the electronic transport of a ZnO nanowire film based structure. A thermionic-field electron emission mechanism is employed to fit and explain the as-observed UV sensitive electronic transport properties of ZnO film with surface-modulation by oxygen and water molecular coverage.
We theoretically study the structural, electronic, and optical properties of lithium niobate under pressure using the plane-wave pseudopotential density functional theory by CASTEP code. It was found that there is a phase transition from the R3 c structure to the Pnma structure at a pressure of 18.7 GPa. The Pnma structure was dynamically stable according to the calculation of phonon dispersion. From the charge density distributions, there exist covalent interactions along the Nb–O bond. The hybridization between O 2p and Nb 4d orbital in the Pnma phase increases with increasing pressure, while it is not changed in the R3c phase. With increasing pressure, the average Nb–O bond length decreases and the Nb–O bond population increases, indicating the increased covalent character between Nb and O atoms under high pressure at Pnma phase, which leads to the increased hybridization between O 2p and Nb 4d orbitals. Furthermore, the optical dielectric function, refractive index, extinction coefficient, electron energy, loss and reflectivity are calculated.
The tunable multiple plasmon-induced transparency （PIT） effect is investigated numerically in a metal-insulator-metal （MIM） waveguide with three side-coupled rectangular resonators. The system exhibits dual-mode PIT effects in the visible and near-infrared regions. By adjusting the geometrical parameters of the structure, we can manipulate not only each single PIT window, but also the double PIT windows simulta- neously. Our structures may have potential applications for optical communication, integrated optics, and optical information processing. The finite element method （FEM） illustrates our theoretical design.
