% 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{Gne:877853,
      author       = {Güneş, Mehmet and Smirnov, V. and Finger, F. and
                      Brüggemann, R.},
      title        = {{T}he effects of air, oxygen and water exposure on the
                      sub-bandgap absorption, the electronic conductivity and the
                      ambipolar diffusion length in highly crystalline
                      microcrystalline silicon films for photovoltaic
                      applications},
      journal      = {Journal of materials science / Materials in electronics},
      volume       = {31},
      number       = {5},
      issn         = {1573-482X},
      address      = {Dordrecht [u.a.]},
      publisher    = {Springer Science + Business Media B.V},
      reportid     = {FZJ-2020-02477},
      pages        = {3960 - 3975},
      year         = {2020},
      abstract     = {Reversible and irreversible changes due to long term air
                      and short term de-ionized water (DIW) or pure oxygen
                      exposure were investigated in about 1 µm thick hydrogenated
                      microcrystalline silicon (µc-Si:H) films deposited on rough
                      glass substrates, thereby comparing highly crystalline with
                      compact material. Time and temperature dependent dark
                      conductivity, steady-state photoconductivity, the
                      steady-state photocarrier grating and dual-beam
                      photoconductivity methods have been used to study the
                      effects. Standard measurement procedures defined previously
                      have been carefully applied to record the changes after
                      different treatments using the steady-state methods under
                      light. After long term air exposure of highly crystalline
                      µc-Si:H films, a thermal annealing step leads to an
                      increase in dark conductivity (σD) and steady-state
                      photoconductivity (σph) as well as to a significant
                      increase in the sub-bandgap absorption. These effects are
                      likely due to a reversible recovery from surface adsorbents
                      in a porous microstructure after air exposure resulting in
                      surface charge and Fermi level shifts in agreement with
                      earlier results. Compact µc-Si:H films showed only marginal
                      effects upon an annealing after long term air exposure
                      suggesting much reduced susceptibility to surface adsorbent
                      induced by Fermi level shifts. Five hours exposure to
                      de-ionized water at 80 °C caused more than an order of
                      magnitude increase in σD and σph and a substantial
                      decrease in the sub-bandgap absorption spectrum in highly
                      crystalline as well as in compact µc-Si:H films. In
                      addition, minority carrier diffusion lengths measured by the
                      steady-state photocarrier grating method improved
                      significantly. The changes after exposure to water were not
                      reversible upon our standard annealing procedure. Exposure
                      to high purity oxygen gas at 150 °C resulted in similar
                      effects like the exposure to DIW. Also here the changes in
                      material properties were not reversible upon annealing.
                      Results are discussed in terms of adsorption and chemical
                      reactions on surfaces in the porous highly crystalline
                      material versus the materials with more compact structures.
                      Results are compared to earlier observations and
                      consequences for device application will be indicated.},
      cin          = {IEK-5},
      ddc          = {620},
      cid          = {I:(DE-Juel1)IEK-5-20101013},
      pnm          = {121 - Solar cells of the next generation (POF3-121)},
      pid          = {G:(DE-HGF)POF3-121},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000510371800002},
      doi          = {10.1007/s10854-020-02944-4},
      url          = {https://juser.fz-juelich.de/record/877853},
}