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Growth and field emission study of molybdenum oxide nanostars

Khademi, A ; Sharif University of Technology | 2009

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  1. Type of Document: Article
  2. DOI: 10.1021/jp9056237
  3. Publisher: 2009
  4. Abstract:
  5. The field emission properties of MoO2 nanostars grown on a silicon substrate and their emission performance in various vacuum gaps are reported in this article. A new structure of molybdenum oxides, named a nanostar, is grown by thermal vapor deposition with a length of ̃1 μm, a thickness of ̃50 nm, and its width in the range of 500-700 nm. The morphology, structure, composition, and chemical states of the prepared nanostars were characterized by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). According to XRD analysis, the grown nanostructures are composed of both crystalline Mo4O11 and crystalline MoO2 structures. XPS analysis showed that the synthesized nanostructures contained ̃21.2% Mo6+, ̃16.2% Mo5+, ̃39.8% Mo4+, and ̃22.8% Mo δ+ (where 0 < δ < 4). TEM observations indicate that the synthesized sample consists of MoO2 nanostars over a crystalline thin film containing Mo4O11 nanoparticles. The turn-on emission field and the enhancement factor of nanostars are found to be 1.0 V/μm and 19 070 at the vacuum gap of 500 μm, respectively. These excellent emission properties are attributed to the special structure of the nanostars. Therefore, these nanostars can be used in vacuum microelectronic applications. © 2009 American Chemical Society
  6. Keywords:
  7. Chemical state ; Crystalline thin films ; Emission performance ; Emission properties ; Enhancement factor ; Field emission property ; In-vacuum ; Molybdenum oxides ; Nanostar ; New structures ; Silicon substrates ; Special structure ; TEM observations ; Thermal vapor depositions ; Vacuum gap ; XPS analysis ; XRD analysis ; Crystalline materials ; Field emission ; High resolution transmission electron microscopy ; Microelectronics ; Molybdenum ; Molybdenum compounds ; Nanostructures ; Scanning electron microscopy ; Vacuum ; Vacuum applications ; X ray diffraction ; X ray diffraction analysis ; X ray photoelectron spectroscopy
  8. Source: Journal of Physical Chemistry C ; Volume 113, Issue 44 , 2009 , Pages 19298-19304 ; 19327447 (ISSN)
  9. URL: https://pubs.acs.org/doi/10.1021/jp9056237