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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.

On the basis of ab initio calculation, we reported the structural and electronic properties of the nickel (Ni) substitution on the cobalt oxide (Co3O4) to produce nickel cobaltite (NiCo2O4) using generalized gradient approximation + U parameter (GGA + U) calculation method. The spinel NiCo2O4 with half-metallic behaviour has a relatively small band gap ∼0.64eV which is spotted decreased from pure Co3O4 band gap 1.26eV. This is due to nickel doping decreased the band gap which also implies that an increase in electrical conductivity. Owing to good electrical conductivity, NiCo2O4 thus enables to be considered for application in supercapacitor. Analysis of the partial density of states (PDOS) shows the differences contributions of cobalt (Co) at the tetrahedral site (Td) and Ni at the conduction bands: Co(Td) ions not affected the majority spin which is in contrast with Ni ions.