A study of the inclusion of prelayers in InGaN/GaN single- and multiple-quantum-well structures

Matthew J. Davies, Philip Dawson, Fabien C.-P. Massabuau, Adrian Le Fol, Rachel A. Oliver, Menno J. Kappers, Colin J. Humphreys

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We report on the effects on the optical properties of blue-light emitting InGaN/GaN single- and multiple-quantum-well structures including a variety of prelayers. For each single-quantum-well structure containing a Si-doped prelayer, we measured a large blue shift of the photoluminescence peak energy and a significant increase in radiative recombination rate at 10 K. Calculations of the conduction and valence band energies show a strong reduction in the built-in electric field across the quantum well (QW) occurs when including Si-doped prelayers, due to enhancement of the surface polarization field which opposes the built-in field. The reduction in built-in field across the QW results in an increase in the electron–hole wavefunction overlap, increasing the radiative recombination rate, and a reduction in the strength of the quantum confined Stark effect, leading to the observed blue shift of the emission peak. The largest reduction of the built-in field occurred for an InGaN:Si prelayer, in which the additional InGaN/GaN interface of the prelayer, in close proximity to the QW, was shown to further reduce the built-in field. Study of multiple QW structures with and without an InGaN:Si prelayer showed the same mechanisms identified in the equivalent single-quantum-well structure.
Original languageEnglish
Pages (from-to)866-872
Number of pages7
JournalPhysica Status Solidi B
Issue number5
Early online date14 Nov 2014
Publication statusPublished - 31 May 2015


  • GaN
  • InGan
  • photoluminescence
  • quantum wells
  • thin films


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