title: Controlled fabrication of core-shell TiO2/C and TiC/C nanofibers on Ti foils and their field-emission properties.
abstract: Core-shell TiO(2)/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 TiO(2)/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-shell TiO(2)/C and TiC/C NFs to ensure strong bonding and small contact resistance between the Ti substrate and the core-shell field emitters. The core-shell TiC/C and TiO(2)/C nanofibers have similar morphology and structure, but the TiC/C nanofibers possess better field emission properties with a turn on field (E(to)) of 2.2 V/μm compared to an E(to) of 3.2 V/μm measured from the TiO(2)/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.
authors.affiliation: Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
authors.forename: Xuming
authors.initials: X
authors.lastname: Zhang
authors.forename: Kaifu
authors.initials: K
authors.lastname: Huo
authors.forename: Hairong
authors.initials: H
authors.lastname: Wang
authors.forename: Biao
authors.initials: B
authors.lastname: Gao
authors.forename: Jijiang
authors.initials: J
authors.lastname: Fu
authors.forename: Tak-Fu
authors.initials: TF
authors.lastname: Hung
authors.forename: Paul K
authors.initials: PK
authors.lastname: Chu