Improved optical and structural properties of nonpolar a-plane AlGaN epi-layers after Cp 2 Mg and NH 3 treatments

The optical and structural properties of non-polar a-plane Al0.4Ga0.6N epi-layers were improved significantly with the assistance of a bicyclopentadienyl-magnesium (Cp2Mg) and ammonia (NH3) (BA) treatment. The defects-related emission was remarkably suppressed with the introduced BA treatment. Moreover, the crystalline quality could be improved significantly using a BA treatment at a relatively low-temperature (LT), whereas the anisotropy in crystalline quality could be suppressed remarkably using a BA treatment at a relatively high-temperature (HT). In fact, the full width at half maximum values in the X-ray rocking curves measured along c- and m-directions were found to be decreased by approximately 15.5% and 56.0%, respectively, with the introduction of both LT-BA and HT-BA treatments. Meanwhile, the root-mean-square value measured with an atomic force microscope was decreased from 7.1 to 3.3 nm due to the LT-BA and HT-BA treatments.