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@PHDTHESIS{Schmitz:977415,
      author       = {Schmitz, Hans Michael},
      othercontributors = {Stampfer, Christoph and Morgenstern, Markus},
      title        = {{CVD}-grown graphene in high magnetic fields},
      school       = {RWTH Aachen University},
      type         = {Dissertation},
      address      = {Aachen},
      publisher    = {RWTH Aachen University},
      reportid     = {RWTH-2024-00704},
      pages        = {1 Online-Ressource : Illustrationen},
      year         = {2024},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University; Dissertation, RWTH Aachen University, 2024},
      abstract     = {The chemical vapor deposition (CVD) on metal catalyst
                      surfaces is the most promising candidate to enable scalable
                      growth of the two-dimensional (2D) carbon allotrope graphene
                      (Gr), thereby opening the door to applications on industrial
                      scales not realizable by the tape exfoliation techniques
                      commonly applied to cleave micrometer sized Gr flakes from
                      bulk graphite crystals. However, the widely employed wet
                      methods to transfer CVD-grown Gr (CVD-Gr) onto arbitrary
                      substrates were demonstrated to degrade its structural and
                      electronic quality precluding industrial harvesting of its
                      various fascinating properties and even casting doubts over
                      the intrinsic quality of CVD-Gr and its suitability for
                      high-quality (HQ) applications. This thesis aims to prove
                      the equality of the intrinsic capabilities of CVD-Gr and the
                      exfoliated reference material by employing and improving the
                      recently introduced dry-transfer method for CVD-Gr, which
                      allows a direct pick-up from the metal growth substrate and
                      subsequent encapsulation in other 2D-materials, thus
                      avoiding the quality degradation associated with wet
                      transfers. Electronic transport devices patterned from such
                      heterostructures were characterized in temperature-dependent
                      magneto-transport measurements in a high magnetic field
                      laboratory. Quantum Hall effect (QHE) measurements reveal a
                      clear formation of Landau levels (LLs) that is overlayed
                      upon increasing magnetic field and decreasing temperature by
                      symmetry-broken LLs and, finally, by a series of clearly
                      pronounced fractional quantum Hall states with composite
                      fermion filling factors up to $\nu^* = 4$ and activation
                      gaps well comparable with those observed in similar devices
                      based on exfoliated graphene (Ex-Gr). These data prove for
                      the first time that the quantum mobilities of CVD-Gr match
                      those of Ex-Gr if a suitable transfer method is applied.
                      Discarding fears of intrinsic differences to Ex-Gr, the
                      CVD-Gr devices could be used as a HQ references within a set
                      of other graphene devices hosting varying level of disorder.
                      In a series of further high magnetic fields measurements,
                      the crucial role of long range disorder for the
                      manifestation of the QHE at room temperature (RT) could be
                      clarified, as an increasingly pronounced effect was observed
                      with increasing disorder level and the QHE vanishing in the
                      HQ CVD-Gr devices well below 150 K at 30 T. In a similar
                      study on the device set, a transition of the predominant
                      scattering mechanism in the RTQHE regime from an extrinsic,
                      disorder-mediated to an intrinsic, electron-phonon mediated
                      scattering mechanism with decreasing disorder level could be
                      revealed.},
      cin          = {132110 / 130000},
      ddc          = {530},
      cid          = {$I:(DE-82)132110_20140620$ / $I:(DE-82)130000_20140620$},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.18154/RWTH-2024-00704},
      url          = {https://publications.rwth-aachen.de/record/977415},
}