Browsing by Author "Lee, Chung-Yang"

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Heterogeneous and Homogeneous Nucleation of Epitaxial NiSi(2) in [110] Si Nanowires
(2011-01-20)
Chou, Yi-Chia
;
Wu, Wen-Wei
;
Lee, Chung-Yang
;
Liu, Chun-Yi
;
Chen, Lih-Juann
We report here both heterogeneous and homogeneous nucleation of epitaxial suicide of NiSi(2) in Si nanowires grown in [110] direction by in situ observation in high-resolution transmission electron microscopy (TEM). Owing to the excellent lattice match between Si and NiSi(2), a giant epitaxial step of 2-8 nm wide forms at the interface between Si and NiSi(2) during the growth of the latter. The step formation results in two suicide/Si interfaces parallel to each other in TEM observations. Heterogeneous nucleation of NiSi(2) occurs at the intersection where the step meets the interfaces. However, we have also observed the epitaxial growth of NiSi(2) having a single interface with the Si, i.e., without a giant step. Homogeneous nucleation of NiSi(2) occurs on the single interface. Incubation time of heterogeneous nucleation of NiSi(2) has been measured by high-resolution video to be much shorter than that of homogeneous nucleation. The overall growth rate of NiSi(2) for the case of heterogeneous nucleation is faster than that for the case of homogeneous nucleation. Kinetic analysis of both types of nucleation is presented for a direct comparison in order to have a better understanding of the nucleation events.
Heterogeneous and Homogeneous Nucleation of Epitaxial NiSi2 in [110] Si Nanowires
(2011-01-20)
Chou, Yi-Chia
;
Wu, Wen-Wei
;
Lee, Chung-Yang
;
Liu, Chun-Yi
;
Chen, Lih-Juann
We report here both heterogeneous and homogeneous nucleation of epitaxial suicide of NiSi2 in Si nanowires grown in [110] direction by in situ observation in high-resolution transmission electron microscopy (TEM). Owing to the excellent lattice match between Si and NiSi2, a giant epitaxial step of 2-8 nm wide forms at the interface between Si and NiSi2 during the growth of the latter. The step formation results in two suicide/Si interfaces parallel to each other in TEM observations. Heterogeneous nucleation of NiSi2 occurs at the intersection where the step meets the interfaces. However, we have also observed the epitaxial growth of NiSi2 having a single interface with the Si, i.e., without a giant step. Homogeneous nucleation of NiSi2 occurs on the single interface. Incubation time of heterogeneous nucleation of NiSi2 has been measured by high-resolution video to be much shorter than that of homogeneous nucleation. The overall growth rate of NiSi2 for the case of heterogeneous nucleation is faster than that for the case of homogeneous nucleation. Kinetic analysis of both types of nucleation is presented for a direct comparison in order to have a better understanding of the nucleation events.
Microwave-assisted Electroless Deposition of Silver Nanoparticles onto Multiwalled Carbon Nanotubes
(2012-05-01)
Wu, Chung-Shu
;
Lee, Chung-Yang
;
Chen, Jem-Kun
;
Kuo, Shiao-Wei
;
Fan, Shih-Kang
In this study, an efficient microwave-assisted self-organization of silver nanoparticles onto multiwalled carbon nanotubes (MWCNTs) is proposed. Silver nanoparticles anchor onto the surface of MWCNTs through self-assembly at the reaction condition of 160 degrees C. We mixed the MWCNTs with saturated silver nitrate/nitric acid solution, without adding a reductant or stabilizer, and then heated them in the closed microwave heating system. The oxidizing conditions create active sites on the surface of MWCNTs and the silver nanoparticles spontaneously align at these sites through electroless deposition. The growing nanoparticles have fcc structures and their density increases upon increasing the reaction time.
Vertically well-aligned epitaxial Ni(31)Si(12) nanowire arrays with excellent field emission properties
(2008-09-15)
Lee, Chung-Yang
;
Lu, Ming-Pei
;
Liao, Kao-Feng
;
Wu, Wen-Wei
;
Chen, Lih-Juann
Vertically well-aligned single crystal Ni(31)Si(12) nanowire (NW) arrays were epitaxially grown on Ni(31)Si(12) films preferentially formed on Ni foil substrates with a simple vapor phase deposition method in one step. The Ni(31)Si(12) NWs are several micrometers in length and 50-80 nm in diameter. The resistivities of the Ni(31)Si(12) NWs were measured to be 51 mu Omega cm by four-terminal electrical measurement. The NWs can carry very high currents and possess excellent field emission properties. The growth of vertically well-aligned Ni(31)Si(12) NW arrays shall lead to significant advantages in the fabrication of vertical Si nanodevices. (C) 2008 American Institute of Physics.