Effects of growth temperature on high-quality In0:2Ga0:8N layers by plasma-assisted molecular beam epitaxy

High-quality In0.2Ga0.8N epilayers were grown on a GaN template at temperatures of 520 and 580 °C via plasma-assisted molecular beam epitaxy. The X-ray rocking curve full widths at half maximum (FWHM) of (10.2) reflections is 936 arcsec for the 50-nm-thick InGaN layers at the lower temperature. When the growth temperature increases to 580 °C, the FWHM of (00.2) reflections for these samples is very narrow and keeps similar, while significant improvement of (10.2) reflections with an FWHM value of 612 arcsec has been observed. This improved quality in InGaN layers grown at 580 °C is also reflected by the much larger size of the crystalline column from the AFM results, stronger emission intensity as well as a decreased FWHM of room temperature PL from 136 to 93.9 meV.