Many material and electronic contributions must be favorable to produce devices with strong quantum Hall effect (QHE) plateaus that are suitable for precise resistance metrology. Even so, metrologically interesting QHE plateaus have been observed in semiconductor heterostructures and in graphene carbon-monolayer based devices fabricated using a variety of different synthesis processes. In graphene devices the QHE has been observed even at room temperature, well above the temperature at which quantum behavior disappears in the best conventional semiconductor-based devices. We are developing the capability to synthesize graphene as an epitaxial layer on SiC and describe some of the necessary conditions, including selection and preparation of the substrate, synthesis environment, and temperature. Our intent is to make available graphene devices for electrical metrology that can operate over a wide range of current and temperature at relatively weak magnetic fields, and to provide subsequent device characterization for primary standards of electrical resistance based on monolayer graphene. Measurements of the plateau flatness and temperature dependence of the Hall resistance in GaAs-AlGaAs heterostructures and a chemical vapor deposition (CVD)-grown graphene monolayer device are presented.
Citation: Kvantovaya Elektronika
Issue: ISSN 0033-2089
Pub Type: Journals
Graphene, quantum Hall effect, electron mobility, heterostructute