Effect of RF power on the properties of transparent conducting zirconium-doped zinc oxide films prepared by RF magnetron sputtering

Transparent and conducting zirconium-doped zinc oxide films with high transparency and relatively low resistivity have been successfully prepared by radio frequency (RF) magnetron sputtering at room temperature. The RF power is varied from 75 to 150W. At first the crystallinity and conductivity of the film are improved and then both of them show deterioration with the increase of the RF power. The lowest resistivity achieved is 2.07×10^-3\Omegacm at an RF power of 100W with a Hall mobility of 16cm²V^-1s^-1 and a carrier concentration of 1.95×10²⁰cm^-3. The films obtained are polycrystalline with a hexagonal structure and a preferred orientation along the c-axis. All the films have a high transmittance of approximately 92% in the visible range. The optical band gap is about 3.33eV for the films deposited at different RF powers.     

New observations on hydrogen bonding in ice by density functional theory simulations

In this paper, we report on a series of computational simulations on hydrogen bonding in two ice phases （Ih and Ic） using CASTEP with PW91 and RPBE exchange-correlation based on ab initio density functional theory. The strength of the H-bond is correlated with intramolecular O-H stretching, and the energy splitting exists for both the H-bond and covalent O-H stretching. By analyzing the dispersion relationship of to（q）, we observe the separation of the longitudinal optic （LO） mode from transverse optic （TO） mode at the gamma point, seemingly interpreting the controversial two H-bond peaks in the vibrational spectrum of ice recorded by inelastic incoherent neutron scattering experiments. The test of ambient environment on phonon density of sates （PDOS） shows that the relaxed tetrahedral structure is the most stable structural configuration for water clusters.