We employ our simulation framework TDKP/AQUA to investigate bulk, planar quantum-well and V-groove quantum-wire light-emitting diodes. Carrier transport and spontaneous light emission are calculated self-consistently for all degrees of quantization. The simulation is based on a semi-coherent picture of drift and diffusion along unquantized directions whereas confinement and luminescence are calculated from a multiband Schroedinger equation in the confined directions. The three structures with different quantization degrees are compared with respect to light conversion efficiency and overall output power. It is shown that carrier confinement greatly improves the radiative conversion efficiency but at the same time limits output power and enhances carrier leakage into the minority regions due to a reduced density of states.
In this contribution, a detailed analysis of optical gain in InGaN/GaN quantum structures with Indium content of 10%
and 20% is presented. Experimental data are obtained from
Hakki-Paoli characterization of edge-emitting Fabry-Perot
lasers. A gain model that includes many-particle effects on a microscopic level, as well as combined quantum-well and
quantum-dot density of states, is used to explain the experimental findings. Inhomogeneous broadening arising from
local Indium clusters is included via a statistical fluctuation of the electronic density of states. Excellent agreement is
obtained for the characteristic gain spectra from structures emitting at 405nm (10% In content) and 470nm (20% In
content), and a systematic analysis of the microscopic physics shows signature of quantum-dot states.