Examining epitaxial graphene surface conductivity and quantum Hall device stability with Parylene passivation

Published: March 20, 2018

Author(s)

Albert F. Rigosi, Chieh-I Liu, Bi Y. Wu, Hsin Y. Lee, Mattias Kruskopf, Yanfei Yang, Heather M. Hill, Jiuning Hu, Emily G. Bittle, Jan Obrzut, Angela R. Hight Walker, Randolph E. Elmquist, David B. Newell

Abstract

When it comes to the advancement of quantized Hall resistance (QHR) standards, homogeneous, single-crystal, monolayer epitaxial graphene (EG) is the most promising candidate. EG-based quantum Hall devices, though emerging as a useful tool for metrology, are electrically unstable when devices are exposed to air due to the adsorption of and interaction with atmospheric molecular dopants. After adsorption, the carrier density will frequently approach the Dirac point or continue to cross into the p-type regime. By stabilizing various electrical properties, such as the surface conductivity, carrier density, and mobility, EG-based devices can be more suitable for long term metrological applications. This work evaluates the use of Parylene C and Parylene N as passivation layers for EG. The two forms of measuring encapsulated graphene are electronic transport of EG quantum Hall devices and non-contact microwave perturbation measurements of millimeter-sized areas of EG. The reported results, showing a significant improvement in passivation due to Parylene deposition, are strongly relevant and significant for the mass production of millimeter-scale graphene devices with stable electrical properties.
Citation: Microelectronic Engineering
Volume: 194
Pub Type: Journals

Keywords

epitaxial graphene, quantum Hall effect, transport mobility, longitudinal resistivity, Parylene
Created March 20, 2018, Updated June 18, 2018