Surface evolution of NaCl-type cubic AlN films on MgO (100) substrates deposited by laser molecular beam epitaxy

► Highly oriented c-AlN film was successfully prepared on MgO (100) substrates by LMBE. ► c-AlN surfaces display the Stranski-Krastanov growth mode. ► Apparent gaps on top of 3D islands are observed in the islands growth. ► A smooth surface grown for 2 h is obtained for the spread and coalescence of islands.