A field emission triode device has been fabricated using self-organized nanodot arrays as the electron emission source. Uniform nanodot arrays of titanium oxide were prepared from the Al/Ti film stack on silicon substrates by electrochemical anodization. The field emission triodes with titanium oxide nanodot emitters exhibited a low gate turn-on voltage of 45 V and high emission current density of 25 mA/cm(2) at 120 V. The excellent electric properties and easily controllable fabrication process of the nanodot triodes show potential applications for field emission displays and vacuum microelectronics. (c) 2005 The Electrochemical Society.