Direct evidence for shallow acceptor states with nonspherical symmetry in GaAs.

نویسندگان

  • G Mahieu
  • B Grandidier
  • D Deresmes
  • J P Nys
  • D Stiévenard
  • Ph Ebert
چکیده

We investigate the energy and symmetry of Zn and Be dopant-induced acceptor states in GaAs using cross-sectional scanning tunnelling microscopy (STM) and spectroscopy at low temperatures. The ground and first excited states are found to have a nonspherical symmetry. In particular, the first excited acceptor state has a T(d) symmetry. Its major contribution to the STM empty-state images allows us to explain the puzzling triangular shaped contrast observed in the empty-state STM images of acceptor impurities in III-V semiconductors.

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عنوان ژورنال:
  • Physical review letters

دوره 94 2  شماره 

صفحات  -

تاریخ انتشار 2005