Papers by Author: Ajis Lepit

Abstract: In this work, seeded porous silicon (PSi) was used as a substrate in the growth of ZnO nanostructures. PSi was prepared by electrochemical etching method. ZnO thin films as seeded were deposited via sol-gel spin coating method. ZnO nanostructures were grown on seeded PSi using hydrothermal immersion method. In order to study the effect of post-heat treatment on the substrate, post annealing temperature were varied in the range of 300 to 700 °C. The FESEM results shows ZnO thin film composed of nanoparticles were distributed over the PSi surface. Based on AFM characterization, the smoothest surface was produced at post annealing temperature of 500 °C. There are two different peaks appeared in PL characterization. The peak in near-UV range is belonging to ZnO thin films while a broad peak in visible range can be attributed to ZnO defects and PSi surface. In addition, FESEM, XRD and PL were used to characterize the ZnO nanostructures. The FESEM results revealed ZnO nano-flower were successfully grown on seeded PSi. Hexagonal wurtzite of ZnO with dominated by the plane (100), (002), and (101) was found by XRD characterization. Two different peaks in UV range and visible range can be attributed to ZnO nano-flower and various defects of ZnO, respectively.

Abstract: γγψγRadiation-Induced grafting of high energy γ-rays onto proton conducting polymer electrolyte membranes (PEMs)-based poly(vinylidene flouride) (PVDF) immersed in 1-Vinylimidazole (VIm) solution have been studied. The different concentrations of VIm from 0.5 to 3.0 M in 1,4-dioxane were prepared. The samples were then exposed to γ-rays from 20 to 100 kGy. The properties of the membranes were characterized based on degree of grafting, spectroscopic study, surface morphology, and X-ray diffraction (XRD) measurement. The degree of grafting (DoG) increased in the PVDF membrane associated with absorbed dose. The results showed that the surface morphology of the membrane observed homogenous when grafting with VIm the after irradiation that compliment with XRD study.