• 文献标题:   Electrical transport properties of graphene nanowalls grown at low temperature using plasma enhanced chemical vapor deposition
  • 文献类型:   Article
  • 作  者:   ZHAO R, AHKTAR M, ALRUQI A, DHARMASENA R, JASINSKI JB, THANTIRIGE RM, SUMANASEKERA GU
  • 作者关键词:   pecvd, thermopower, resistivity, graphene nanowall
  • 出版物名称:   MATERIALS RESEARCH EXPRESS
  • ISSN:   2053-1591
  • 通讯作者地址:   Univ Louisville
  • 被引频次:   8
  • DOI:   10.1088/2053-1591/aa6ee1
  • 出版年:   2017

▎ 摘  要

In this work, we report the electrical transport properties of uniform and vertically oriented graphene (graphene nanowalls) directly synthesized on multiple substrates including glass, Si/SiO2 wafers, and copper foils using radio-frequency plasma enhanced chemical vapor deposition (PECVD) with methane (CH4) as the precursor at relatively low temperatures. The temperature for optimum growth was established with the aid of transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy. This approach offers means for low-cost graphene nanowalls growth on an arbitrary substrate with the added advantage of transfer-free device fabrication. The temperature dependence of the electrical transport properties (resistivity and thermopower) were studied in the temperature range, 30-300 K and analyzed with a combination of 2D-variable range hopping (VRH) and thermally activated (TA) conduction mechanisms. An anomalous temperature dependence of the thermopower was observed for all the samples and explained with a combination of a diffusion term having a linear temperature dependence plus a term with an inverse temperature dependence.