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A new route to synthesis of Ag2O micro-/nanostructures, including a mixture of cubes, pyramids, triangular plates, pentagonal rods, and bars, has been developed by pulsed excimer laser ablation of bulk silver in water using polysorbate 80 as surfactant. The polysorbate 80 played an important role in the formation of the Ag2O structures, and similar structures could be obtained in polysorbates 20 and 40 aqueous solutions. We have proposed a mechanism to explain the formation of Ag2O structures. This laser ablation method provides a unique approach to discover and fabricate new Ag2O morphologies. [ABSTRACT FROM AUTHOR]

Charge carrier lifetime is a critical parameter to improve the conversion efficiency of radioisotope power sources and the sensitivity of neutron detectors based on boron carbide thin films. The effective charge carrier lifetime in B4C boron carbide films has been investigated by using transient photoconductivity decay. The carrier lifetime depends on the characterization conditions as well as the structure of the films. The measured lifetime could be up to ∼1 ms in B4C film, which is much longer than that in conventional semiconductors. The photoresistance change in B4C films and the photovoltaic response of B4C/n-Si(100) heterojunctions have also been studied. [ABSTRACT FROM AUTHOR]

We report on the formation of hollow MgO particles by excimer laser ablation of bulk Mg in water and aqueous solutions of sodium dodecyl sulfate (SDS) and sodium citrate (SC). Lamellar nanostructures of Mg(OH)2 also formed in water, but the formation could be avoided by the addition of SDS or SC. Laser ablation produced not only Mg species that were oxidized into MgO and Mg(OH)2 in water, but also cavitation bubbles. The bubble interfaces trapped the MgO nanoparticles to decrease the surface free energy of the system, finally resulting in hollow particles. [ABSTRACT FROM AUTHOR]