Optical gain in 407nm and 470nm InGaN/GaN heterostructures: signature of quantum-dot 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.