(002) Oriented-aluminum nitride (AlN) films with different thicknesses were deposited on tungsten (W) tips by using radio frequency magnetron reactive sputtering system. Compared studies of field emission (FE) characteristics were performed between the bare and AlN coated W tips. The results showed that enhanced electron emission could be obtained from oriented-AlN film on W tip. The hysteresis behaviors shown in Current-electric field (I-E) curves during downward electric field sweeps were observed, and the extent of hysteresis in I-E curves strongly depended on the thickness of the AlN film. The stability measurement of FE current presented that the hysteresis could be attributed to the charging in AIN film as an insulator. (c) 2005 Elsevier B.V. All rights reserved.