Electron-hole plasma emission from ${\mathrm{In}}_{0.3}{\mathrm{Ga}}_{0.7}\mathrm{N}/\mathrm{G}\mathrm{a}\mathrm{N}$ multiple quantum wells

${\mathrm{In}}_{0.3}{\mathrm{Ga}}_{0.7}\mathrm{N}/\mathrm{G}\mathrm{a}\mathrm{N}$ multiple quantum wells have been grown on the epitaxial lateral overgrowth GaN successfully. The samples have been characterized by transmission electron microscopy and x-ray diffraction, which show the high quality of the samples. Photoluminescence measurements have been carried out at room temperature, with back scattering geometry. At a low excitation power, only exciton-related emission has been observed at 3.1935 eV. With increasing excitation power, a peak appears at the low-energy side of the exciton-related emission, and becomes dominant at high excitation power. This peak has been assigned to plasma emission, because the intensity of this peak increases with excitation power as $I_{\mathrm{ex}}^{1.9}.$