Shallow and deep defects in AlxGa1-xN structures

We report electrical characterization of AlxGa1-xN materials grown by MOCVD. The techniques used in this study were admittance spectroscopy and photocurrent measurements. We identify a continuum of shallow donors with ionization energies ranging from 50 to 110meV in AlxGa1-xN alloys with values of t...

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Bibliographic Details
Published in:Physica. B, Condensed matter Condensed matter, 2007-12, Vol.401-402, p.335-338
Main Authors: Seghier, D, Gislason, H P
Format: Article
Language:English
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Summary:We report electrical characterization of AlxGa1-xN materials grown by MOCVD. The techniques used in this study were admittance spectroscopy and photocurrent measurements. We identify a continuum of shallow donors with ionization energies ranging from 50 to 110meV in AlxGa1-xN alloys with values of the Al mole fraction x=0.1 and 0.3. Investigations of the photocurrent buildup kinetics allow identification of a deep center with optical ionization energy of 1.2eV. This center controls the buildup of the photocurrent when the materials are illuminated with sub-bandgap photon energy. In the light of this finding we discuss the broad spectrum of DX-like defects that may contribute to the persistent photocurrent and the collapse in the drain current observed in AlGaN-related structures.
ISSN:0921-4526
DOI:10.1016/j.physb.2007.08.181