Formation of p-type MgZnO by nitrogen doping

A wurtzite N-doped MgZnO film with 20 at. % Mg (MgZnO:N) was grown by plasma-assisted molecular beam epitaxy on c-plane sapphire using radical NO as oxygen source and nitrogen dopant. The as-grown MgZnO:N film behaves n-type conduction at room temperature, but transforms into p-type conduction after annealed for 1 h at 600 degrees C in an O-2 flow. The p-type MgZnO:N has a hole concentration of 6.1x10(17) cm(-3) and a mobility of 6.42 cm(2)/V s. X-ray photoelectron spectroscopy measurement indicates that substitution of N for O site is in forms of N atom (N)(O) and N molecule (N-2)(O) for the as-grown MgZnO:N, but almost only in a form of (N)(O) for the annealed MgZnO:N. The mechanism of the conduction-type transition induced by annealing is discussed in the present work. (c) 2006 American Institute of Physics.