Electronic Properties of Epitaxial Graphene Grown on SiC

• Main Authors: Chieh-I Liu, 劉玠沂
• Other Authors: 梁啟德
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/53544671501009820121

博士 === 國立臺灣大學 === 應用物理研究所 === 105 === The remarkable properties of epitaxial graphene (EG) growth on SiC shows promising prospects of application in future electronics. This dissertation focuses on the electronic properties of EG. I begin with a basic knowledge of graphene along with necessary background for the research. There will be demonstrations of sample preparations and experimental setups. The experimental results described in this thesis are divided into three parts. The first topic involves charge trapping, weak localization and electron-electron interactions on EG. Activation energies ΔE for charge trapping in epitaxial graphene ranging from 196meV to 34meV. It is shown that ΔE decreases with increasing mobility indicates the importance of sample quality. Different scattering channels can be recognized by studying the weak localization. Also, it is found that both the zero-field resistance and the WL correction term can be used as reliable thermometers. In the high-temperature regime, a logarithmic temperature (lnT) dependence of the Hall slope is a good physical quantity which allows us to investigate electron-electron interactions. The study on variable range hopping (VRH) and non-linear transport in monolayer epitaxial graphene is described in the second topic. The resistance curve derivative analysis method can be used to determine whether Mott VRH or Efros-Shklovskii VRH is the dominant transport mechanism in the linear regime. In the non-linear regime in which the conductance shows a strong dependence on voltage, it is found that the experimental results can be well described by existing theoretical models. The last topic describes the preliminary results on Parylene C encapsulation. The weak interactions on the interface of Parylene C/graphene shows Parylene C is a suitable encapsulated material. Besides, surface conductance measurement provides a faster and convenient way to characterize longitudinal resistivity of large-area graphene samples. The variations in quantities after exposing to environmental chamber and ambient air shows room for improvement in adhesion between Parylene C and graphene.