Fig. 1. Formation mechanism of composite structures of InGaAs well clusters. (a) InGaAs well-cluster composite structure; (b) surface topography of 2D growth mode; (c) 3D cluster

Fig. 2. Experimental setup

Fig. 3. PL spectra under different carrier densities and Gaussian fitting results. (a) PL spectra measured from dual-facets of WCC structure; (b) Gaussian fitting results of PL spectra

Fig. 4. Material gain and quasi-Fermi separation of WCC nanostructure and traditional InGaAs/GaAs quantum well structure.(a) Material gain curves; (b) quasi-Fermi separation and ratio

Fig. 5. Asymmetric energy-band structure