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Built‐in fields in stacked InGaN/GaN quantum dots
Author(s) -
Schulz Stefan,
O'Reilly Eoin P.
Publication year - 2011
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201000915
Subject(s) - quantum dot , materials science , sign (mathematics) , rectangular potential barrier , piezoelectricity , condensed matter physics , optoelectronics , physics , composite material , mathematics , mathematical analysis
The built‐in potential ϕ tot of an isolated and of three stacked lens‐shaped c ‐plane In 0.2 Ga 0.8 N/GaN quantum dots (QDs) is calculated using a surface integral approach. There remains disagreement about the sign of the shear strain piezoelectric coefficient e 15 , with more recent analysis suggesting e 15 < 0. We show that with e 15 < 0, the potential ϕ tot changes sign outside an isolated QD, in contrast to the case with e 15 > 0. This behaviour affects ϕ tot in a system of stacked QDs. For small barrier thicknesses between the QDs, the potential in the central QD is strongly reduced compared to an isolated QD, independent of the sign of e 15 . Using e 15 < 0 and small barrier thicknesses, the potential in the remaining two QDs is also slightly reduced, while for larger barrier thicknesses almost no reduction is observed.