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Fabrication, Characterization and Field Emission Study of GLAD Tungsten Nanostructures

Shaker, Tayebeh | 2011

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 41827 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Moshfegh, Alireza; Azimirad, Ruhollah
  7. Abstract:
  8. Recently nanostructure materials have used in various technologies and hence an extensive part of research focused on preparing and optimization of growth of nanostructure materials. Usually common procedure is based on a two-step process. First, construction a pre-layer by means of different deposition methods and then formation a nanostructure with a thermal treatment which increases the cost of research. Hence with one step method such as glancing angle deposition (GLAD ( it is possible to form a desirable structure with low cost. In this research Nano columns of tungsten was deposited on Si(133) by means of GLAD-RF sputtering without any heat treatment at substrate rotational speed ( ) from 2 to 33 RPM . Argon pressure was about 13 -2 Torr and tilted angle of substrate was fixed at 75 . AFM and SEM analysis show that with increasing , the diameter of nanocolumns reaches to the lowest optimum value of 33 nm at 1 RPM and it increases with increasing . XRD analysis shows the deposited nanocolumns are made of nanocrystal with approximately 3 nm in size in -phase. XPS confirms the surface layer is tungsten oxide. Application of nanoculumns in field emission was investigated in different athode-anode spacing from 53 to 153 under UHV conditions. aximum field enhancement factor ( ) of 2783 was obtained at d = 153
  9. Keywords:
  10. Tungsten ; Field Emission ; Nanocolumns ; Glancing Angle Deposition (GAD)-Sputtering Method

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