Detail publikace

HfO2 nanostructure arrays via porous-alumina-assisted anodization of hafnium layers

MOZALEV, A. BENDOVÁ, M. GISPERT-GUIRADO, F. LLOBET, E.

Originální název

HfO2 nanostructure arrays via porous-alumina-assisted anodization of hafnium layers

Typ

abstrakt

Jazyk

angličtina

Originální abstrakt

Hafnium dioxide (HfO2) due to its excellent electrical and optical properties complemented by chemical and thermal stability is a promising material in the fields of electroceramics, optics, and electronics. Nanostructuring of hafnium oxide opens more opportunities for creating functional materials with new properties and applications. Here we report, for the first time, the formation of HfO2 nanostructures aligned on substrates via the porous-anodic-alumina (PAA)-assisted anodization of hafnium layers prepared by magnetron sputtering. A layer of Hf followed by a layer of Al sputtered onto a SiO2 substrate (an Al/Hf bilayer) is used as the initial sample. In the anodizing approach, the aluminum layer is first converted to PAA [ ], then the Hf film is oxidized through the alumina nanopores. A major difficulty is that anodic HfO2 films are crystalline, and the transport number for Hf4+ cation is almost zero (0.05). These result in undesired oxygen evolution and hinder oxide penetration into the pores. To overcome the above obstacles, an appropriate combination of technological, electrical, and electrolytic conditions was developed so as to allow for nucleation and sustainable growth of PAA-assisted HfO2 nanostructures not only beneath the alumina layer but also inside the pores, which then could be released from the PAA overlayer by selective chemical etching, as shown in Fig. 1. More morphological and size variations arise from altering the anodizing variables at both the PAA formation and PAA-assisted hafnium oxidation stages, the details to be fully explored in due course. The ionic transport, film morphology, chemical composition, crystal structure, and electrical/dielectric properties of the PAA-assisted HfO2 nanofilms are being examined to develop and justify the model of film nucleation and growth, and approach potential applications.

Klíčová slova

anodizing;hafnium oxide

Autoři

MOZALEV, A.; BENDOVÁ, M.; GISPERT-GUIRADO, F.; LLOBET, E.

Vydáno

11. 7. 2017

Strany počet

1

BibTex

@misc{BUT144050,
  author="Alexander {Mozalev} and Mária {Bendová} and Francesc {Gispert-Guirado} and Eduard {Llobet}",
  title="HfO2 nanostructure arrays via porous-alumina-assisted anodization of hafnium layers",
  booktitle="Book of abstracts of Anodize it! Conference",
  year="2017",
  pages="1",
  note="abstract"
}