Národní úložiště šedé literatury Nalezeno 3 záznamů.  Hledání trvalo 0.01 vteřin. 
Effect of EU doping on the optical properties of ZnO nanorods prepared by chemical bath deposition
Yatskiv, Roman ; Bašinová, Nikola ; Grym, Jan ; Vaniš, Jan
We report on the properties of Eu-doped ZnO nanorods prepared by chemical bath deposition from aqueous solutions in an autoclave. The autoclave enables to grow the nanorods above the boiling point of water. The nanorods were characterized by scanning electron microscopy, secondary ion mass spectroscopy, and low temperature photoluminescence spectroscopy. Under the UV light excitation, the nanorods show a strong blue emission at 450 nm, which is associated with the 4f(6)5d - 4f(4) transitions of Eu2+ ions. We discuss the mechanisms responsible for the blue luminescence. We further clarify how the growth parameters affect the morphology and the optical properties of the nanorods. Growth temperatures above the boiling point of water significantly influence the intensity ratio of the near band edge emission to the deep level emission and greatly enhance optical quality of the nanorods.
Effect of heat treatment on the properties of sol-gel deposited ZnO seed layers
Bašinová, Nikola ; Černohorský, Ondřej ; Grym, Jan ; Maixner, J.
Zinc oxide nanorods as a potential material for nanoscale devices are prepared by chemical bath deposition (CBD). The effect of the quality of the sol-gel deposited seed layer on the vertical alignment of the nanorods to a silicon substrate is discussed. Emphasis is put on the investigation of the impact of the heat treatment on the properties of the seed layer deposited by dip-coating. The sol-gel method is a multi-stage process consisting of three principal steps: (i) preparation of a solution with suitable precursors, (ii) deposition of the precursor solution, and (iii) the heat treatment. The preheating needs to be performed to thermally decompose the zinc acetate precursor into zinc oxide seeds. Three different temperatures of preheating are compared (300 degrees C, 350 degrees C, 400 degrees C) followed by annealing in argon at 800 degrees C and the influence on the quality of the seed layers and vertical alignment of nanorods are discussed. When the preheating temperature is higher than 350 degrees C, the seed layer comprises smaller and denser crystallites with a preferential orientation along the c-axis. CBD growth of ZnO nanorods on these seed layers results in their good vertical alignment
Influence of H2O2 treatment on morphological and photoluminescence properties of hydrothermally grown ZnO nanorods
Yatskiv, Roman ; Grym, Jan
We report photoluminescence properties of hydrothermally grown ZnO nanorods (NRs) before and after hydrogen peroxide (H2O2) treatment. The H2O2 treatment introduces oxygen related defects and thus enhances chemisorption processes in ZnO NRs. These effects amplify interactions between the gas species and adsorbed oxygen and thus can influence sensing properties of ZnO NRs