Structure and pholuminescence properties of ZnS-core / In2O3-shell one-dimensional nanowires

초록

Zinc Sulfide (ZnS) is an important II-VI semiconductor with a wide direct band gap (3.7 eV) at room temperature having received significant attention over the past few decades. ZnS has potential applications in flat panel displays, infrared windows, ultraviolet light-emitting diodes and injection lasers, phosphors in cathode-ray tubes, electroluminescent thin film devices, and sensors owing to its intense luminescence, high refractive index, and high transmittance properties in the visible range. ZnS is also promising for room temperature exciton devices because of the large exciton binding energy (38 meV) in comparison with the room temperature thermal energy (25 meV). Various techniques have been employed to synthesize one-dimensional (1D) ZnS nanostructures such as thermal evaporation of ZnS powder, solvothermal process, chemical vapor deposition, electrochemical deposition, and template-assisted routes [1], etc. It is essential to passivate one-dimensional (1D) nanostructures with insulating materials to avoid crosstalking between the building blocks of complex nanoscale circuits as well as to protect them from contamination and oxidation . ZnS-core/ In2O3-shell nanowires were synthesized by the thermal evaporation of ZnS powders followed by the sputter deposition of In2O3 and the structure and influence of thermal annealing on the photoluminescence properties of were investigated. We performed scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDXS), and photoluminescence spectroscopy to characterize the ZnS-core/ In2O3-shell nanowires. TEM and XRD analyses revealed that the cores and shells of the core-shell nanowires were single crystal zinc blende-type ZnO and amorphous In2O3, respectively. PL measurement at room temperature showed that the core-shell nanowires had a green emission band centered at around 525 nm with a shoulder at around 385 nm. The PL emission of the co