Influence of coating and annealing on the optical properties of ZnSe/CdO core-shell nanorods

초록

ZnSe is an important wide direct band gap compound semiconductor which has attracted significant interest for their potential applications in optoelectronics and electronics. ZnSe is particularly suitable for short-wave optoelectronic device applications including blue green laser diodes and tunable mid-IR laser sources for remote sensing. Recently one-dimensional (1D) nanostructures of ZnSe such as nanowires, nanorods, nanobelts, nanoribbons, nanoneedles, have been synthesized using various techniques including thermal evaporation, metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), pulsed lased deposition (PLD), atomic layer deposition (ALD), and a chemical method via solution-liquid-solid mechanism [1]. We can give one-dimensional (1D) nanostructures various functions that can be used effectively for nanoscale electronic or optoelectronic devices by sheathing them with other materials to make core-shell 1D nanostructures. For example, the PL emission intensity of the light emitted from coaxial nanostructures can be significantly increased or the wavelength of the emission can be controlled by selecting a proper sheathing material and optimizing the sheath layer thickness In this paper, we report the synthesis, structure, and photoluminescence properties of ZnSe-core/CdO-shell nanorods synthesized by a two-step process comprising the thermal evaporation of ZnSe powders and the sputter-deposition of CdO for the first time . The ZnSe nanorods have been grown by the thermal evaporation of ZnSe powders on gold-coated Al2O3 (0001) substrates. The ZnSe-core/CdO-shell nanorods were 0.1-0.2 µm in diameter and up to a few tens of micrometers in length. Transmission electron microscopy and X-ray diffraction analysis results indicate that the cores and shells are single crystal zinc blende-type ZnSe and polycrystalline face-centered cubic-type CdO, respectively. Photoluminescence measurements show that the ZnSe-core/CdO-shell nanorods.