Thumbnail image of graphical abstract

If the ABC model is accepted as a valid tool to analyze the internal quantum efficiency of GaInN/GaN light-emitting diodes, the high-current efficiency must be roughly proportional to the ratio B/C2/3 between the coefficients B and C, which correlate radiative and Auger-like recombination rate with the carrier density. The low efficiency of green diodes compared to blue diodes implies therefore a decreasing B/C2/3 ratio with decreasing bandgap energy. In this study (see the article by Schiavon et al. on pp. 283–290), the recombination rate coefficients were measured in single-quantum-well light-emitting diodes spanning the entire blue-green spectral range. The figure shows the coefficient B corrected for the varying wavefunction overlap as a function of bandgap energy, while the inset shows the photoluminescence of UX:3 chips with different wavelengths. The decrease of B/C2/3 is mostly caused by the decrease of B rather than by the increase of C. Furthermore, a good agreement between the coefficients C of this work and those calculated elsewhere from first principles is found, supporting the conclusion that Auger recombination is the main cause of the high C in GaInN layers.