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Identifier

000305025

Title

Σύνθεση Νανοδομών ZnO σε Υδατικά Διαλύματα και η χρήση τους ως αισθητήρες όζοντος

Alternative Title

Ozone sensing properties of ZnO nanostructures grown by the aqueous chemical growth

Author

Κενανάκης, Γιώργος Δημητρίου

Thesis advisor

Κατσαράκης, Νίκος

Abstract

This MSc. dissertation examines the deposition of zinc oxide nanostructures using aqueous chemical growth technique to study their response to ozone atmosphere at mild conditions. The synthesis is a novel, low-cost and environmentally-friendly aqueous method, which enables the generation of advanced metal oxide thin films, at large-scale and moderate conditions. The study emphasizes on several deposition parameters such as the time of growth, the kind of the substrates and the acidity of the solutions. ZnO samples are studied regarding their structural and morphological characteristics, while their response to ozone is examined through electrical measurements. Depending on the deposition conditions, ZnO with hexagonal wurtzite structure is obtained. The samples’ morphology varies from nanorods to flowerlike nanostructures and nanotubes. Under ultraviolet irradiation and subsequent exposure to ozone atmosphere, the samples show electrical current changes of three up to six orders of magnitude. The highest ozone response of the ZnO nanostructures, which is defined as the ratio of the electrical current I in the photoreduction (Iph) and oxidation (Io) states (S= Iph/Io) reaches 106, depending on their surface-to-volume ratio, surface morphology, average thickness and substrate coverage. It is concluded that ZnO nanostructured samples deposited by aqueous chemical growth at low temperatures give promising results regarding room temperature ozone sensing.

Language

Greek

Subject

Aqueous chemical growth

Nanostructures

Ozone sensing

ZnO

Ανίχνευση όζοντος

Ζinc oxide

Νανοδομές

Οξείδιο του ψευδαργύρου

Σύνθεση σε υδατικά διαλύματα (ACG)