• 文献标题:   Quality assessment of terahertz time-domain spectroscopy transmission and reflection modes for graphene conductivity mapping
  • 文献类型:   Article
  • 作  者:   MACKENZIE DMA, WHELAN PR, BOGGILD P, JEPSEN PU, REDOSANCHEZ A, ETAYO D, FABRICIUS N, PETERSEN DH
  • 作者关键词:  
  • 出版物名称:   OPTICS EXPRESS
  • ISSN:   1094-4087
  • 通讯作者地址:   Tech Univ Denmark
  • 被引频次:   9
  • DOI:   10.1364/OE.26.009220
  • 出版年:   2018

▎ 摘  要

We present a comparative study of electrical measurements of graphene using terahertz time-domain spectroscopy in transmission and reflection mode, and compare the measured sheet conductivity values to electrical van der Pauw measurements made independently in three different laboratories. Overall median conductivity variations of up to 15% were observed between laboratories, which are attributed mainly to the well-known temperature and humidity dependence of non-encapsulated graphene devices. We conclude that terahertz time-domain spectroscopy performed in either reflection mode or transmission modes are indeed very accurate methods for mapping electrical conductivity of graphene, and that both methods are interchangeable within measurement uncertainties. The conductivity obtained via terahertz time-domain spectroscopy were consistently in agreement with electrical van der Pauw measurements, while offering the additional advantages associated with contactless mapping, such as high throughput, no lithography requirement, and with the spatial mapping directly revealing the presence of any inhomogeneities or isolating defects. The confirmation of the accuracy of reflection-mode removes the requirement of a specialized THz-transparent substrate to accurately measure the conductivity. (c) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement