The Structural and Optical Properties of High-Al-Content AIInGaN Epilayers grown by RF-MBE

摘要

AIInGaN Quaternary Alloys were successfully grown on sapphire substrate by radio-frequency plasma-excited molecular beam epitaxy (RF-MBE). Different Al content AIInGaN quaternary alloys were acquired by changing the Al cell's temperature. The streaky RHEED pattern observed during AIInGaN growth showed the layer-by-layer growth mode. Rutherford back-scattering spectrometry (RBS), X-Ray diffraction (XRD) and Cathodoluminescence (CL) were used to characterize the structural and optical properties of the AIInGaN alloys. The experimental results show that the AIInGaN with appropriate Al cell's temperature, could acquire Al/In ratio near 4.7, then could acquire better crystal and optical quality. The samllest X-ray and CL full-width at half-maximum (FWHM) of the AIInGaN are 5arcmin and 25nm, respectivly. There are some cracks and V-defects occur in high-Al/In-ratio AIInGaN alloys. In the CL image, the cracks and V-defect regions are the emission-enhanced regions. The emission enhancement of the cracked and V-defect regions may be related to the In-segregation.