Fabrication du (Zn,M)O par recuit d'un film mince de M déposé par évaporation sur du ZnO (M = Co ou Mn, (inédit))

Student thesis: DEA typesDEA in Physics and material Chemistry

Abstract

The aim of this work was to investigate the structural properties of (Zn,M)O layers obtained by diffusion of thin films (~ 1nm) of M (M = Mn or Co) into ZnO by annealing. The samples were characterised in-situ by scanning tunnelling microscopy (STM), Auger electron spectroscopy (AES), low energy electron diffraction (LEED) and ex-situ by time of flight secondary ion mass spectroscopy (ToF-SIMS) and X-ray diffraction (XRD). From the evolution of the intensity of M, Zn and O Auger lines upon annealing and thanks to modelling of the attenuation of Auger lines by matter we could estimate the diffusion depth of M into ZnO under various conditions. The results of the model were then compared to ToF-SIMS depth profiles. In the case of Co/ZnO, annealing at a temperature higher than 945 K leads to the diffusion of Co into ZnO and to the substitution of Zn by Co. According to our results a ~3nm thick (Zn0,5Co0,5)O layer forms upon annealing. In addition ToF-SIMS depth profiles show that minute amount of Co may diffuse to a depth of 25 nm after prolonged annealing. Finally although surface reconstructions were observed by LEED, no binary phase could be evidenced by XRD. In the case of Mn/ZnO, from 800 K, the substitution of Zn by Mn is observed and a thin ZnMnO layer forms. Diffusion of minute amount of Mn is observed 10 nm below the surface. In addition, LEED patterns show Moiré structures.
Date of Award2007
LanguageFrench
SupervisorRobert Sporken (Supervisor)

Cite this

Fabrication du (Zn,M)O par recuit d'un film mince de M déposé par évaporation sur du ZnO (M = Co ou Mn, (inédit))
Mugumaoderha Cubaka, M. (Author). 2007

Student thesis: DEA typesDEA in Physics and material Chemistry