文摘
Core鈥搒hell TiO2/C and TiC/C nanofibers are fabricated in situ on Ti and Al ion-implanted Ti substrates by a thermochemical reaction in acetone and the growth mechanism is described. Implantation of Al into Ti leads to in situ growth of TiC/C in lieu of TiO2/C nanofibers. This is because Al has a higher affinity to oxygen than Ti and Ti reacts preferentially with C to form TiC. The Ti foil serves as both the Ti source and substrate for the core鈥搒hell TiO2/C and TiC/C NFs to ensure strong bonding and small contact resistance between the Ti substrate and the core鈥搒hell field emitters. The core鈥搒hell TiC/C and TiO2/C nanofibers have similar morphology and structure, but the TiC/C nanofibers possess better field emission properties with a turn on field (Eto) of 2.2 V/渭m compared to an Eto of 3.2 V/渭m measured from the TiO2/C nanofibers. The enhanced field-emission property of the TiC/C nanofibers is attributed to the high electrical and thermal conductivity of the TiC inner core, which provides a more effective electron transfer pathway between the cathode and C shell emitters.
Keywords:
TiO2/C and TiC/C core鈭抯hell nanostructures; fabrication; electron field emission