Browsing by Author "Lo, PY"

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Localized lateral growth of single-walled carbon nanotubes for field-effect transistors by a cobalt-mix-TEOS method
(2005)
Chen, BH
;
Lo, PY
;
Wei, JH
;
Tsai, MJ
;
Hwang, CL
Lateral-growth carbon nanotubes (CNTs) were fabricated in a pre-assigned area using an integrated circuit compatible method. In order to synthesize single wall carbon nanotubes (SWNT) for the fabrication of a field-effect transistor (FET), the cobalt-mix-tetraethoxysilane (TEOS) (CMT) solution is proposed. The CMT solution has the unique property of dispersing the cobalt (Co) catalyst well and uniformly embedding it in a predetermined location after the CMT solution has solidified. The lateral growth of bundle-SWNT could be formed in atmospheric chemical vapor deposition (APCVD) with ethanol. (c) 2005 The Electrochemical Society.
Semiconducting single-walled carbon nanotubes exposed to distilled water and aqueous solution: Electrical measurement and theoretical calculation
(2006-01-30)
Lu, MP
;
Hsiao, CY
;
Lo, PY
;
Wei, JH
;
Yang, YS
We fabricate and measure a single-walled carbon nanotube transistor having a liquid-gate electrode. The ratio value of I-on/I-off is as high as 10(4), indicating the presence of a semiconducting channel. A passivation layer over the source/drain electrode greatly suppresses the liquid-gate leakage by about three orders of magnitude. The channel currents are noticeably distinct between two liquid samples: distilled water and aqueous solution (1x10(-4) M NaCl). This biological sensing ability is attributed to the different electrical double-layer capacitances with respect to the bulk part of the channel. The corresponding theoretical calculation is carried out in detail. (c) 2006 American Institute of Physics.
Structure and property features of the catalyst-assisted carbon nanostructures on Si wafer by catalyst ion implantation and ECR-CVD
(2005-03-01)
Lin, CC
;
Lo, PY
;
Lin, CH
;
Kuo, CT
;
材料科學與工程學系
Experiments to examine effects of ion-implanted catalyst on the structure and property features of carbon nanotubes (CNTs) and nanostructures on Si wafer were conducted by electron cyclotron resonance chemical vapor deposition (ECR-CVD) with CH4 and H-2 as source gases, under both ion-implanted and PVD-coated catalysts with different H-plasma pretreatment conditions. The deposited CNTs and substrates at every processing step were characterized by FESEM, TEM, SIMS, XRD and Raman spectroscopy. The results show that the growth mechanism of the CNTs under condition with the ion-implanted catalyst is different from that with the PVD-coated catalyst. It results in a greater hollow size of the tubes for the former condition. Furthermore, under conditions of a higher catalyst dosage and higher H-plasma concentration pretreatment, it indicates better field emission properties, more Co-silicide formation and more percentage of base-growth CNTs due to an increase in the amount of Co source and process temperature. The main effect of the implanted catalyst is essentially to enhance the adhesion strength of CNTs with the substrate through the Co-silicide formation and embedding the catalyst into the substrate, as shown by XRD and SIMS analyses. Additionally, it is also favor to form CNTs with a lower I-D/I-G ratio and so a lower defect density. Under the present conditions, the best field emission properties are: turn-on voltage similar to 6 V/mu m and current density > 0.72 mA/cm(2). In summary, the structure, growth mode, adhesion strength with the substrate, defect density and field emission properties of CNTs can be manipulated by changing the ion-implantation dosages and H-plasma pretreatment conditions, which may not be able to be produced by other methods. (c) 2005 Elsevier B.V. All rights reserved.