Electron microscopy determination of crystallographic polarity of aluminum nitride thin films.

Aluminum nitride (AlN) crystallizes usually in the wurtzite structure (P6mc) and it has a crystallographic polarity. In this work, the polarity in AlN was characterized by using several methods of transmission electron microscopy (TEM) in order to examine their applicability. AlN was deposited by metalorganic vapor phase epitaxy (MOVPE), followed by annealing at 1550 °C.