Speaker
Description
Recent advances in nanotechnology enable novel nanomaterials for developing new scintillators. Outstanding scintillator materials require high absorption cross-section, fast response and robust radiation tolerance and good scalability. ZnO with fast decay time (<1ns) was proposed for ultrafast X-ray imaging. However, some applications require extremely high frame rate in the GHz range. We proposed to develop and perform some initial experiments on new types of ZnO based nanocomposites to reduce its response time. The nanocomposites consist of metallic nanoparticles such as Au, Ag embedded in ZnO films. To guide our experimental efforts, we first performed simulations on different metal/ZnO nanostructures. We have compared the effects of the metallic nanoparticle sizes, nanoparticle types and distances between the nanoparticles and ZnO structures. Simulation results show that Purcell effect, or shorter radiation time can be achieved by introducing of metal nanoparticles. We have fabricated Ag:ZnO nanocomposite films with Ag nanoparticles in ZnO film matrix have been grown on glass substrates by using pulsed laser deposition and spin-coating methods. To maximize the Purcell effect, we have systematically controlled the diameter and the density of Ag nanoparticles in nanocomposites by the growth temperature and thermal annealing. The structural properties have been characterized by X-ray diffraction and scanning transmission electron microscopy. We have investigated the scintillating properties including the decay time and photoluminescence using various charged particle and light sources.
