Direct experimental determination of the spontaneous polarization of GaN

Jonas Lähnemann*, Oliver Brandt, Uwe Jahn, Carsten Pfüller, Claudia Roder, Pinar Dogan, Frank Grosse, Abderrezak Belabbes, Friedhelm Bechstedt, Achim Trampert, Lutz Geelhaar

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

77 Scopus citations

Abstract

We present a universal approach for determining the spontaneous polarization P sp of a wurtzite semiconductor from the emission energies of excitons bound to the different types of stacking faults in these crystals. Employing microphotoluminescence and cathodoluminescence spectroscopy, we observe emission lines from the intrinsic and extrinsic stacking faults in strain-free GaN microcrystals. By treating the polarization sheet charges associated with these stacking faults as a plate capacitor, P sp can be obtained from the observed transition energies with no additional assumptions. Self-consistent Poisson-Schrödinger calculations, aided by the microscopic electrostatic potential computed using density-functional theory, lead to nearly identical values for P sp. Our recommended value for P sp of GaN is -0.022±0.007 C/m2.

Original languageEnglish (US)
Article number081302
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume86
Issue number8
DOIs
StatePublished - Aug 9 2012

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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