Determination of the charge carrier compensation mechanism in Te-doped GaAs by scanning tunneling microscopy
نویسندگان
چکیده
We identified the charge carrier compensation mechanism in Te-doped GaAs with atomically resolved scanning tunneling microscopy. Three types of defects were found: tellurium donors (TeAs), Ga vacancies (VGa), and Ga vacancy–donor complexes (VGa– TeAs). We show quantitatively that the compensation in Te-doped bulk GaAs is exclusively caused by vacancy– donor complexes in contrast to Si-doped GaAs. This is explained with the Fermi-level effect as the universal mechanism leading to Ga vacancy formation in n-doped GaAs, and a Coulomb interaction leading to the formation of the complexes. The quantification of the carrier compensation yields a 23e charge state of VGa in bulk GaAs. © 2003 American Institute of Physics. @DOI: 10.1063/1.1563835#
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