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Influence of strain in the reduction of the internal electric field in GaN/AlN quantum dots grown on a ‐plane 6H‐SiC
Author(s) -
Cros A.,
Budagosky J. A.,
GarcíaCristóbal A.,
Garro N.,
Cantarero A.,
Founta S.,
Mariette H.,
Daudin B.
Publication year - 2006
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200565103
Subject(s) - wurtzite crystal structure , electric field , quantum dot , materials science , piezoelectricity , raman spectroscopy , condensed matter physics , polarization (electrochemistry) , bar (unit) , optoelectronics , zinc , chemistry , optics , physics , composite material , quantum mechanics , metallurgy , meteorology
The strain state of stacks of GaN/AlN quantum dots (QDs) grown on (0001) and (11 $ \bar 2 $ 0) 6H‐SiC has been investigated by means of Raman spectroscopy. Depending on the orientation of the wurtzite axis with respect to the growth direction it is found that the piezoelectric contribution to the electrostatic potential may either reinforce that arising from the spontaneous polarization or oppose it. The experimental results are compared with a theoretical model for the strain and polarization field in QDs of both orientations that allows the calculation of the electrostatic potential in the QDs. Both the experimental results and the theoretical model indicate that the internal electric field and electrostatic potential are strongly reduced in the QDs grown on (11 $ \bar 2 $ 0) 6H‐SiC as compared to those grown along the wurtzite c ‐axis. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)