Electrical properties of nanocrystalline GaN film prepared by magnetron sputtering

Nanocrystalline GaN film was prepared by direct current magnetron sputtering. X-ray diffraction and transmission electron microscopy confirmed the presence of hexagonal phase GaN crystallites with particle size of 5 nm. The I–V characteristic of the Al/nc-GaN contacts can be understood in terms of the current transport mechanism of space-charge-limited current. Analysis of the I–V data indicates an equilibrium electron concentration of 8.1 × 1014 cm−3 and the thermal equilibrium Fermi level located 0.27 eV below the conduction band edge. Only one deep level located at 0.364 eV below the conduction band with capture cross-section of 1.74 × 10−18 cm2 was found in the film by Q-DLTS. A simple analysis has been used to identify this deep level.