Origins of blue and violet luminescence in AlN films grown by MOCVD and the impact of a small amount of Ga doping

Aluminum nitride (AlN) has attracted considerable attention for its promising applications in short-wavelength optoelectronic devices. However, undesirable blue and violet luminescence from MOCVD-grown AlN films has impeded their development. This study has experimentally investigated the blue luminescence at 2.7 eV originated from the donor-acceptor pair (DAP) transitions between V Al acceptor and deep donors, and the violet luminescence at 3.0eVoriginated from the transitions between Al(NO y ) x complex and conduction band or shallow donor level. Additionally, incorporating a small amount of Ga into the AlN layer during the growth can modulate the defect types and suppress violet luminescence. This study is crucial for improving the performance of AlN-based optoelectronic devices.