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@ARTICLE{Hajlaoui:903607,
      author       = {Hajlaoui, Mahdi and Ponzoni, Stefano and Deppe, Michael and
                      Henksmeier, Tobias and As, Donat Josef and Reuter, Dirk and
                      Zentgraf, Thomas and Springholz, Gunther and Schneider,
                      Claus Michael and Cramm, Stefan and Cinchetti, Mirko},
      title        = {{E}xtremely low-energy {ARPES} of quantum well states in
                      cubic-{G}a{N}/{A}l{N} and {G}a{A}s/{A}l{G}a{A}s
                      heterostructures},
      journal      = {Scientific reports},
      volume       = {11},
      number       = {1},
      issn         = {2045-2322},
      address      = {[London]},
      publisher    = {Macmillan Publishers Limited, part of Springer Nature},
      reportid     = {FZJ-2021-05261},
      pages        = {19081},
      year         = {2021},
      abstract     = {Quantum well (QW) heterostructures have been extensively
                      used for the realization of a wide range of optical and
                      electronic devices. Exploiting their potential for further
                      improvement and development requires a fundamental
                      understanding of their electronic structure. So far, the
                      most commonly used experimental techniques for this purpose
                      have been all-optical spectroscopy methods that, however,
                      are generally averaging in momentum space. Additional
                      information can be gained by angle-resolved photoelectron
                      spectroscopy (ARPES), which measures the electronic
                      structure with momentum resolution. Here we report on the
                      use of extremely low-energy ARPES (photon energy ~ 7 eV) to
                      increase depth sensitivity and access buried QW states,
                      located at 3 nm and 6 nm below the surface of cubic-GaN/AlN
                      and GaAs/AlGaAs heterostructures, respectively. We find that
                      the QW states in cubic-GaN/AlN can indeed be observed, but
                      not their energy dispersion, because of the high surface
                      roughness. The GaAs/AlGaAs QW states, on the other hand, are
                      buried too deep to be detected by extremely low-energy
                      ARPES. Since the sample surface is much flatter, the ARPES
                      spectra of the GaAs/AlGaAs show distinct features in
                      momentum space, which can be reconducted to the band
                      structure of the topmost surface layer of the QW structure.
                      Our results provide important information about the
                      samples’ properties required to perform extremely
                      low-energy ARPES experiments on electronic states buried in
                      semiconductor heterostructures.},
      cin          = {PGI-6},
      ddc          = {600},
      cid          = {I:(DE-Juel1)PGI-6-20110106},
      pnm          = {5212 - Emergent Quantum Phenomena (POF4-521)},
      pid          = {G:(DE-HGF)POF4-5212},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {34580361},
      UT           = {WOS:000700619200021},
      doi          = {10.1038/s41598-021-98569-6},
      url          = {https://juser.fz-juelich.de/record/903607},
}