Abstract: AlInGaN quaternary alloys were successfully grown on sapphire substrate by radiofrequency plasmaexcited molecular beam epitaxy (RF-MBE). AlInGaN quaternary alloys with different compositions were acquired by changing the Al cell’s temperature. The streaky RHEED patterns were observed during AlInGaN quaternary alloys growth. Scanning Electron Microscope (SEM), Rutherford backscattering spectrometry (RBS), X-Ray diffraction (XRD) and Cathodoluminescence (CL) were used to characterize the structural and optical properties of the AlInGaN alloys. The experimental results show that the AlInGaN quaternary alloys grow on the GaN buffer in the layerbylayer growth mode. When the Al cell’s temperature is 920℃, the Al/In ratio in the AlInGaN quaternary alloys is about 4.7，and the AllnGaN can acquire better crystal and optical quality. The X-ray and CL fullwidth at halfmaximum (FWHM) of the AlInGaN are 5arcmin and 25nm, respectively.

Key words: AlInGaN, RF-MBE, structural properties, optical properties