% 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”.

@PHDTHESIS{Skaja:834335,
      author       = {Skaja, Katharina},
      title        = {{R}edox processes and ionic transport in resistive
                      switching binary metal oxides},
      volume       = {49},
      school       = {RWTH Aachen},
      type         = {Dr.},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2017-04310},
      isbn         = {978-3-95806-236-8},
      series       = {Schriften des Forschungszentrums Jülich. Reihe Information
                      / Information},
      pages        = {VII, 203 S.},
      year         = {2017},
      note         = {RWTH Aachen, Diss., 2016},
      abstract     = {The growing demand for non-volatile memories requires new
                      concepts in data storage and mobile computing, as the
                      existing flash technology runs into a physical scaling
                      limit. One of the promising candidates for future
                      non-volatile memories is Redox-based Resistive Random Access
                      Memory (ReRAM). This memory technology is based on a
                      non-volatile and reversible switching of device resistance
                      with an external stimulus. The reversible resistance change
                      in the memristive device can be attributed to an electro
                      reduction, which takes place in the metal oxide and/or at
                      the metal oxide electrode interface. The formation of ionic
                      defects and their motion are involved in the electrically
                      induced redox processes, which for most metal oxides is
                      correlated to a valence change of metal ions. Within this
                      thesis the microscopic processes in memristive devices are
                      investigated in order to understand the defect configuration
                      and defect motion in metal oxide thin films. Furthermore,
                      the redox processes localized in nanoscale filaments induced
                      by field-driven defect motion has been elucidated. The
                      resistive switching characteristic of Ta$_{2}$O$_{5-x}$
                      single layers as well as Nb$_{2}$O$_{5-x}$/
                      Ta$_{2}$O$_{5-x}$ heterostructures has been investigated. It
                      could be demonstrated that the forming voltage of the
                      memristive devices can be modified by different reactive
                      sputtering conditions. During electrical biasing a
                      morphological change with a dendrite-like shape occurs at
                      the top electrode. The formation of this dendrite-like
                      structure at the metal oxide/metal interface, has been
                      correlated to an avalanche discharge induced redox process
                      in the metal oxide. The dendrite-like structure can be
                      assigned to an oxygen deficient amorphous phase of the metal
                      oxide. The predominant defects in TiO$_{2-x}$ are determined
                      by ionic charge compensation at intermediate oxygen partial
                      pressure and dominated by electronic charge compensation at
                      reducing conditions. For Ta$_{2}$O$_{5-x}$ ceramics as well
                      as thin films the electrical conductivity is dominated by
                      ionic charge compensation over the entire investigated
                      oxygen partial pressure range. The formation energy for
                      oxygen vacancies of single crystal/ceramics is comparable to
                      the values of the thin films. At oxidizing conditions the
                      thin films show an enhanced ionic conduction due to an
                      increased concentration of defects at the grain boundaries
                      and an accumulation of the space charges. The equilibration
                      process in TiO$_{2-x}$ single crystals as well as in thin
                      films is dominated by a surface exchange process. The
                      velocity of the equilibration process is influenced by the
                      surface orientation of single crystals. In TiO$_{2-x}$ thin
                      films a two-fold surface exchange process has been
                      identified. As origin of this two-fold process the
                      incorporation or release of a second species such as water
                      was discussed as well as the influence of the texturing of
                      the thin film and the influence of the substrate.},
      cin          = {PGI-7},
      cid          = {I:(DE-Juel1)PGI-7-20110106},
      pnm          = {521 - Controlling Electron Charge-Based Phenomena
                      (POF3-521)},
      pid          = {G:(DE-HGF)POF3-521},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      url          = {https://juser.fz-juelich.de/record/834335},
}