CVD Synthesis of Small-Diameter Single Walled Carbon Nanotubes on Silicon

Source: arXiv

ABSTRACT A simple process for chemical vapor deposition of ultra SD single wall carbon
nanotubes has been developed. In this process, an iron nitrate nonahydrate
solution in isopropyl alcohol with a concentration of 400 ug/mlit was used to
catalyze nanoparticles formation on an oxidized silicon wafer. The oxide on the
substrate was made of a thick layer of wet oxide sandwiched between tow thin
layers of dry oxide. The process results in semiconducting single-walled carbon
nanotubes (SWNTs) with diameter of less than 0.7nm and more than 1ev band gap
energy, which are amongst the smallest diameters of SWNTs ever reported.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Statistics from the NHS Blood and Transplant Annual Review show that total organ transplants have increased to 4213 in 2012, while the number of people waiting to receive an organ rose to 7613 that same year. Human donors as the origin of transplanted organs no longer meet the ever-increasing demand, and so interest has shifted to synthetic organ genesis as a form of supply. This focus has given rise to new generation tissue and organ engineering, in the hope of one day designing 3D organs in vitro. While research in this field has been conducted for several decades, leading to the first synthetic trachea transplant in 2011, scaffold design for optimising complex tissue growth is still underexplored and underdeveloped. This is mostly the result of the complexity required in scaffolds, as they need to mimic the cells' native extracellular matrix. This is an intricate nanostructured environment that provides cells with physical and chemical stimuli for optimum cell attachment, proliferation and differentiation. Carbon nanotubes are a popular addition to synthetic scaffolds and have already begun to revolutionise regenerative medicine. Discovered in 1991, these are traditionally used in various areas of engineering and technology; however, due to their excellent mechanical, chemical and electrical properties their potential is now being explored in areas of drug delivery, in vivo biosensor application and tissue engineering. The incorporation of CNTs into polymer scaffolds displays a variety of structural and chemical enhancements, some of which include: increased scaffold strength and flexibility, improved biocompatibility, reduction in cancerous cell division, induction of angiogenesis, reduced thrombosis, and manipulation of gene expression in developing cells. Moreover CNTs' tensile properties open doors for dynamic scaffold design, while their thermal and electrical properties provide opportunities for the development of neural, bone and cardiac tissue constructs. This review will provide an update on the use of CNTs in 3D organ generation.
    Biotechnology Advances 05/2014; DOI:10.1016/j.biotechadv.2014.05.003 · 8.91 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Synthesis, properties, and applications of ultrasmall particles (USPs, size/diameter <10 nm), so-called “ultrasmall nanoparticles”, are reviewed. USPs mainly consist of nanoparticles (with or without functionalization) of metallic gold, as well as iron and gadolinium oxides, all of which have important biomedical applications. Several other elemental metals and non-metals, oxides, salts, a few polymers and coordination compounds have also been obtained as USPs. Their main applications include biomedical uses {Magnetic Resonance Imaging (MRI) contract agents, virus inactivation, immunoassay labeling, etc.}, varieties of catalysis, hydrogen sorption, as magnetic devices, ultrasmall transistors, sensors for gases or biological objects, parts of solar cells and batteries, among others. Recent approaches, such as size-focusing methodology, for obtaining USPs and preventing their further agglomeration, are discussed.
    RSC Advances 01/2013; 3(45):22648. DOI:10.1039/c3ra43418d · 3.71 Impact Factor
  • Source
    01/2014; DOI:10.4172/2157-7587.1000167