Recombination dynamics in InGaN quantum wells – Contribution of excited subband recombination to carrier leakage. Schulz, T., Nirschl, A., Drechsel, P., Nippert, F., Markurt, T., Albrecht, M., & Hoffmann, A. Applied Physics Letters, 105(18):181109, 2014.
doi  abstract   bibtex   
The recombination dynamics of ${In}_x{Ga}_{1-x}{N}$ single quantum wells are investigated. By comparing the photoluminescence (PL) decay spectra with simulated emission spectra obtained by a Schrödinger-Poisson approach, we give evidence that recombination from higher subbands contributes the emission of the quantum well at high excitation densities. This recombination path appears as a shoulder on the high energy side of the spectrum at high charge carrier densities and exhibits decay in the range of ps. Due to the lower confinement of the excited subband states, a distinct proportion of the probability density function lies outside the quantum well, thus contributing to charge carrier loss. By estimating the current density in our time resolved PL experiments, we show that the onset of this loss mechanism occurs in the droop relevant regime above 20\,A/${cm}^2$.
@article{Schulz2014,
   author = "Schulz, T. and Nirschl, A. and Drechsel, P. and Nippert, F. and Markurt, T. and Albrecht, M. and Hoffmann, A.",
   title = {{Recombination dynamics in InGaN quantum wells -- Contribution of excited subband recombination to carrier leakage}},
   journal = "Applied Physics Letters",
   year = "2014",
   volume = "105",
   number = "18", 
   pages = "181109",
   doi = "10.1063/1.4901256", 
   abstract = {The recombination dynamics of ${In}_x{Ga}_{1-x}{N}$ single quantum wells are investigated. By comparing the photoluminescence (PL) decay spectra with simulated emission spectra obtained by a Schrödinger-Poisson approach, we give evidence that recombination from higher subbands contributes the emission of the quantum well at high excitation densities. This recombination path appears as a shoulder on the high energy side of the spectrum at high charge carrier densities and exhibits decay in the range of ps. Due to the lower confinement of the excited subband states, a distinct proportion of the probability density function lies outside the quantum well, thus contributing to charge carrier loss. By estimating the current density in our time resolved PL experiments, we show that the onset of this loss mechanism occurs in the droop relevant regime above 20\,A/${cm}^2$.}
}

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