Enhanced field emission properties Of MoO2 nanorods with controllable shape and orientation

Arrays of MoO2 nanorods were fabricated on silicon substrates within a typical growth time of similar to1 min by direct heating of a molybdenum spiral coil in a low vacuum. The nanorods grown with Air particles as catalyst have similar diameters but with sharper tips than that grown without catalyst, and exhibit a lower switch-on voltage for field emission. The orientation of the nanorods with sharper tips can be considerably improved by increasing the coil temperatures, thus leading to increased field emission currents. For example, the turn-on voltage of the nanorods decreases from similar to18 to similar to4 V/mum when the coil temperature goes up from similar to800 to similar to1000 degreesC. The present study provides a way to fabricate metal oxides nanorods on flat substrates as well as to modify their field emission performance. (C) 2004 Elsevier B.V. All rights reserved.