Nanomaterials and Nanotechnology

Biography

Biography: Muhammad Arif Khan

Abstract

This research investigates the novel fabrication and controlled growth of vertically aligned ZnO/CuO core-shell heterojunction nanowires (NWs) formation by vapor deposition and oxidation approach. ZnO/CuO heterostructure nanowires were grown on n-type Si substrate using modified thermal chemical vapor deposition (TCVD) assisted by sputtering deposition followed by thermal oxidation under controlled growth conditions. The effects of fabrication parameters on structure, growth mechanism, optical and electrical properties of the ZnO/CuO core-shell heterojunction were thoroughly investigated. Structural characterization by field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HR-TEM), scanning transmission electron microscope (STEM), X-ray photoelectron spectroscope (XPS), X-ray diffractometer (XRD) and energy dispersive X-ray (EDX) reveals that a highly pure crystalline ZnO core and polycrystalline CuO shell were successfully fabricated in which ZnO and CuO are of hexagonal wurtzite and monoclinic structures, respectively. The growth of ZnO nanowires is along the c-axis [002] direction and the nanowires have relatively smooth surfaces with diameters in the range of 35-45 nm and lengths in the range of 700-1300 nm. The CuO nanoshell with thickness of around 8-10 nm is constructed of nanocrystals with sizes in the range of 3–10 nm. The optical, electrical and band offset properties at heterointerface of core-shell heterojunction nanowires were also discussed in details. The research of this study can provide new pathways and presents a simple approach for the fabrication of vertically aligned n-ZnO/p-CuO core-shell heterojunction NWs for the applications such as solar energy conversion and advanced nano-optoelectronic devices.