TechConnectWorld 2011 Conference and Expo TechConnect World 2011 Nanotech 2011 Clean Technology 2011 Microtech 2011 Bio Nanotech 2011 TechConnect Summit and Expo 2011

Controllable Sequential Low Temperature Plasma Assisted Growth of Vertical Multi-wall & Single-wall CNTs

Z. Kolahdouz, S. Darbari, S. Mohajerzadeh
University of Tehran, IR

Keywords: CNTs, PECVD, sequential hydrogenation, S/M/WNT


By investigating the effects of growth parameters of CNTs, we have arrived at small diameter, single/multi-wall nanotubes at low temperatures. Synthesis of CNTs was performed using the gas mixture of the C2H2/CH4 gas and H2 in a DC-PECVD reactor. The physical properties of samples were investigated by HR-SEM, TEM and Raman spectroscopy. The studied parameters were temperature, hydrogenation time, plasma power and catalyst layer thickness. Moreover, a novel sequential hydrogenation/growth process has been developed. CH4 was found more suitable than C2H2 to achieve SWCNTs with widths of 10nm and less. Prior to CNT growth, Ni (1-13nm thickness), as the catalyst seed was conditioned using a sequential process. A dual-step pre-growth treatment of the surface was performed. First, the surface of the sample was treated with a hydrogen-blow for 15 min with the substrate temperature at ~550-700℃, followed by a treatment of hydrogen plasma at the same temperature of the growth in order to create Ni nano-islands. To avoid Ni-grain agglomeration we developed a new method of hydrogenation consists of several sequences of methane flow to temporally passivate the grains to keep the sizes unchanged. Immediately after the two-step pretreatment, CH4 was introduced into the chamber for 12 min to initiate the growth of CNTs.
Sessions Monday Tuesday Wednesday Thursday Authors Keywords Affiliations Search

TechConnect World 2011 Nanotech 2011 Clean Technology 2011 Microtech 2011 BioNanotech 2011 TechConnect Summit 2011
2011 Events | Program | Speaker | Short Courses Sponsor Exhibit/Showcase Press Venue Register
Subscribe | Contact | Site Map
© Copyright 2010 TechConnect World. All Rights Reserved.