Novel solution growth method of bulk AlN using Al and Li₃N solid sources

In this work, we developed a solution growth method that uses Li-Al-N solution to epitaxially grow AlN on a self-nucleated, columnar AlN seed crystal. The seed crystal was grown by physical vapor transport, and the solution was obtained by annealing a Li₃N-Al mixture. The epitaxial AlN grew ∼5 μm in 10 h. Scanning electron microscopy analyses showed that the grown layer had many voids near the epilayer/seed interface, but no evidence of cracks. Using transmission electron microscopy analyses, we found that the growth direction of the AlN was [1100] and the layer had threading dislocation propagating along [1100] with a density of ∼4 × 10⁸ cm ^-2.