AVS 51st International Symposium
    Nanometer-scale Science and Technology Thursday Sessions
       Session NS2-ThM

Paper NS2-ThM11
Strong Field Emission of Taper-Like and Rod-like Si Nanowires Grown on Si@sub X@Ge@sub 1-X@ Substrate

Thursday, November 18, 2004, 11:40 am, Room 213D

Session: Nanowires I
Presenter: Y.-L. Chueh, National Tsing Hua University, Taiwan
Authors: Y.-L. Chueh, National Tsing Hua University, Taiwan
L.J. Chou, National Tsing Hua University, Taiwan
S.L. Cheng, National Tsing Hua University, Taiwan
J.H. He, National Tsing Hua University, Taiwan
W.W. Wu, National Tsing Hua University, Taiwan
L.J. Chen, National Tsing Hua University, Taiwan
Correspondent: Click to Email
Taper-like and rod-like Si nanowires (SiNWs) have been synthesized on Si and Si@sub 0.8@Ge@sub 0.2@ substrate annealed at 1200 °C in N@sub 2@ ambient. The tip regions of taper-like SiNWs are about 5-10 nm in diameter. The average length of the taper-like SiNWs is about 6 µm with aspect ratios is around 150-170. On the other hand, the rod-like is 5-100 nm in diameter, and 4-5 µm in length. The proposed growth models of there nanowires are oxide-assisted growth (OAG) and vapor-liquid-solid (VLS) growth. The taper-like morphology may be created by the passivation of the SiO@sub 2@ coating layer, and resulted in the different levels of absorption of SiO along the nanowires. The formation of metal-catalyst free rod-like SiNW is due to creation of unstable thin SiO@sub x@ layer, which vaporized easily during the annealing process. The optical and field emission characterization of these SiNWs have been investigated and present. Taper-like Si nanowires exhibit a superior field emission with a turn-on field of 6.3-7.3 V/µm and a threshold field of 9-10 V/µm. The @beta@ value are estimated to be 700 and 1000 at low and high fields, respectively. The excellent field emission characteristics are attributed to the perfect crystalline structure and taper-like geometry of the Si nanowires.