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Keywords:

  • GaN;
  • inhomogeneous broadening;
  • photoluminescence;
  • quantum wells

Abstract

The influence of two structural inhomogeneities (i.e., the quantum well width and indium concentration fluctuations) on the radiative recombination time (τr) in polar InGaN quantum wells (QWs) was studied within the “random” QW model [M. Gladysiewicz and R. Kudrawiec, J. Phys.: Condens. Matter 22, 485801 (2010)]. In this analysis it is assumed that the τr is inversely proportional to the electron–hole overlap integral which can be calculated within the effective mass approximation. In order to simulate QW inhomogeneities in this model, it was assumed that the QW width and indium concentration vary with a Gaussian distribution where the nominal QW width and indium concentration correspond to the mean value in this distribution and their fluctuations correspond to the deviation from the main value. Obtained results clearly show that the variation of QW width in this system (the first type of QW inhomogeneities) leads to a non-linear dispersion of the τr whereas the change in indium concentration (the second type of QW inhomogeneities) leads to a linear dispersion of the τr. The two types of QW inhomogenities (QW width and indium concentration fluctuations) lead to a situation where the same emission wavelength can be realized by QWs with significantly different τr constants. Such a behavior of the τr leads to a non-exponential decay of photoluminescence.