This thesis work reports an experimental analysis of ZnO nanostructures and ultrathin films on the Au(111) surface, by means of Scanning Tunneling Microscopy (STM). The ZnO/Au(111) system is obtained with two different techniques: Electron Beam Physical Vapor Deposition (EB-PVD) of metallic zinc, which is then oxidized, and Pulsed Laser Deposition (PLD), by ablation of a stoichiometric ZnO target. The study focuses on the synthesis and characterization of the two-dimensional phase assumed by ZnO in these systems, defined Graphene-like Zinc Oxide (g-ZnO), the structural and morphological properties of which are discussed thanks to high-resolution STM images. Emphasis is given to the influence of the different parameters, which characterize the deposition processes, on the morphology of the structures obtained. Experiments are carried out at different coverages, allowing the study of the growth mechanisms of this ZnO phase on the chosen substrate.
Il presente elaborato di tesi riporta un’analisi sperimentale della crescita di nanostrutture e film ultrasottili di ZnO su una superficie Au(111), tramite microscopia a effetto tunnel (STM, Scanning Tunneling Microscopy). Il Sistema ZnO/Au(111) è stato ottenuto con due differenti tecniche: deposizione fisica da vapore da fascio elettronicoo (EB-PVD, Electron Beam Physical Vapor Deposition) di zinco metallico, che è stato poi ossidato, e deposizione a laser pulsato (PLD, Pulsed Laser Deposition), tramite ablazione di un obiettivo stochiometrico di ZnO. Lo studio si focalizza sulla sintesi e sulla caratterizzazione della fase disimensionale assunta da ZnO in questi sistemi, definita ossido di zinco grafenico (g-ZnO, Graphene-like Zinc Oxide), le cui caratteristiche strutturali e morfologiche sono discusse grazie ad immagini STM ad alta risoluzione. E’ stata data enfasi all’influenza dei diversi paramentri, che caratterizzano i processi di deposizione, sulla morfologia delle strutture ottenute. Sono stati eseguiti esperimenti a diversi ricoprimenti, che permettono di studiare le modalità di crescita di questa fase di ZnO sul substrato scelto.
Synthesis and characterization of two-dimensional zinc oxide : a scanning tunneling microscopy study
CRISTINA, RICCARDO
2014/2015
Abstract
This thesis work reports an experimental analysis of ZnO nanostructures and ultrathin films on the Au(111) surface, by means of Scanning Tunneling Microscopy (STM). The ZnO/Au(111) system is obtained with two different techniques: Electron Beam Physical Vapor Deposition (EB-PVD) of metallic zinc, which is then oxidized, and Pulsed Laser Deposition (PLD), by ablation of a stoichiometric ZnO target. The study focuses on the synthesis and characterization of the two-dimensional phase assumed by ZnO in these systems, defined Graphene-like Zinc Oxide (g-ZnO), the structural and morphological properties of which are discussed thanks to high-resolution STM images. Emphasis is given to the influence of the different parameters, which characterize the deposition processes, on the morphology of the structures obtained. Experiments are carried out at different coverages, allowing the study of the growth mechanisms of this ZnO phase on the chosen substrate.File | Dimensione | Formato | |
---|---|---|---|
2015-12-Cristina.pdf
accessibile in internet per tutti
Descrizione: Thesis text
Dimensione
6.5 MB
Formato
Adobe PDF
|
6.5 MB | Adobe PDF | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/115847