Field-emission properties of transparent tungsten oxide nano-urchins

The field-emission properties of transparent tungsten oxide nano-urchin (NU) films deposited on conducting glass substrates were examined. The novel crystalline tungsten oxide NUs consisted of nanowires added to a spherical shell. The WO_2.72 NUs showed better field-emission properties than the WO₃ NUs with a low turn-on field of approximately 5.8 V/μm and a current density as high as 1.3 mA/cm² at 7.2 V/mm. The WO _x NUs films could be used in FE applications using a large-area glass substrate without the need for a catalyst and a mechanical rubbing or lift-up process. These results have implications for the enhancement of FE properties by further tuning the WO _x phases.