% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Krkknen:201480,
      author       = {Kärkkänen, Irina and Shkabko, Andrey and Heikkilä, Mikko
                      and Vehkamäki, Marko and Niinistö, Jaakko and Aslam,
                      Nabeel and Meuffels, Paul and Ritala, Mikko and Leskelä,
                      Markku and Waser, Rainer and Hoffmann-Eifert, Susanne},
      title        = {{I}mpedance spectroscopy study of the unipolar and bipolar
                      resistive switching states of atomic layer deposited
                      polycrystalline {Z}r{O} $_{2}$ thin films},
      journal      = {Physica status solidi / A},
      volume       = {212},
      number       = {4},
      issn         = {1862-6300},
      address      = {Weinheim},
      publisher    = {Wiley-VCH},
      reportid     = {FZJ-2015-03775},
      pages        = {751 - 766},
      year         = {2015},
      abstract     = {The polarity of the resistive switching (RS) characteristic
                      of metal-oxide-metal devices from atomic layer deposited
                      polycrystalline ZrO2 films was studied by means of impedance
                      spectroscopy. Pt/ZrO2/Ti/Pt cells made with 10 nm Ti and
                      30 nm Pt capping top electrodes, served as unipolar
                      switching (US) devices. Bipolar switching (BS) devices were
                      represented by Pt/ZrO2/30 nm TiN cells. Temperature
                      measurements of the ON-state resistances clearly show
                      metallic and semiconducting behavior for the US and BS
                      cells, respectively. The pristine and the ON and OFF states
                      of the devices were analyzed by means of impedance
                      spectroscopy. All ZrO2 based RS devices exhibited similar
                      impedance characteristics in the pristine states. In
                      contrast, after electroforming clear differences in the
                      Nyquist-plots of the US and BS devices were observed. The
                      effect of the device structure on the RS polarity is
                      discussed under consideration of the pillar-shaped grainy
                      microstructure of the ZrO2 thin films. An empirical model
                      based on redox reactions between ZrO2 and the non-noble
                      metal electrode is proposed emphasizing defect formation
                      prior at the ZrO2 grain boundaries.},
      cin          = {PGI-7 / JARA-FIT},
      ddc          = {530},
      cid          = {I:(DE-Juel1)PGI-7-20110106 / $I:(DE-82)080009_20140620$},
      pnm          = {524 - Controlling Collective States (POF3-524)},
      pid          = {G:(DE-HGF)POF3-524},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000352820100008},
      doi          = {10.1002/pssa.201431489},
      url          = {https://juser.fz-juelich.de/record/201480},
}