Exciton localization and the Stokes' shift in InGaN epilayers

R. W. Martin, P. G. Middleton, K. P. O'Donnell, W. Van Der Stricht

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We report a comparative study of the emission and absorption spectra of a range of commercial InGaN light-emitting diodes and high-quality epilayers. A working definition of the form of the absorption edge for alloys is proposed, which allows a unique definition of the Stokes' shift. A linear dependence of the Stokes' shift on the emission peak energy is then demonstrated for InGaN using experimental spectra of both diode and epilayer samples, supplemented by data from the literature. In addition, the broadening of the absorption edge is shown to increase as the emission peak energy decreases. These results are discussed in terms of the localization of excitons at highly indium-rich quantum dots within a phase-segregated alloy.

Original languageEnglish
Pages (from-to)263-265
Number of pages3
JournalApplied Physics Letters
Issue number2
Publication statusPublished - 5 Jan 1999


  • InGaN epilayers
  • light emitting diode
  • Stokes' shift

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