Reactive ZnO/Ti/ZnO interfaces studied by hard x-ray photoelectron spectroscopy

Ronny Knut (1) , Rebecka Lindblad (1) , Sergey Grachev (2) , Jean-Yvon Faou (2) , Mihaela Gorgoi (3) , Hakan Rensmo (1) , Elin Sondergard (2) , Olof Karis (1)

1 Department of Physics and Astronomy [Uppsala]
2 SVI - Surface du Verre et Interfaces
3 HZB - Helmholtz-Zentrum Berlin für Materialien und Energie GmbH = Helmholtz Centre Berlin for Materials and Energy = Centre Helmholtz de Berlin pour les matériaux et l'énergie

The chemistry and intermixing at buried interfaces in sputter deposited ZnO/Ti/ZnO thin layers were studied by hard x-ray photoelectron spectroscopy. The long mean free path of the photoelectrons allowed for detailed studies of the oxidation state, band bending effects, and intrinsic doping of the buried interfaces. Oxidation of the Ti layer was observed when ZnO was deposited on top. When Ti is deposited onto ZnO, Zn Auger peaks acquire a metallic character indicating a strong reduction of ZnO at the interface. Annealing of the stack at 200 C results in further reduction of ZnO and oxidation of Ti. Above 300 C, oxygen transport from the bulk of the ZnO layer takes place, leading to re-oxidation of ZnO at the interface and further oxidation of Ti layer. Heating above 500 C leads to an intermixing of the layers and the formation of a ZnxTiOy compound.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Ronny Knut, Rebecka Lindblad, Sergey Grachev, Jean-Yvon Faou, Mihaela Gorgoi, et al.. Reactive ZnO/Ti/ZnO interfaces studied by hard x-ray photoelectron spectroscopy. Journal of Applied Physics, 2014, 115, pp.043714. ⟨10.1063/1.4854636⟩. ⟨hal-00938244⟩