Quantum Hall effect in millimeter-scale, gateless, monolayer epitaxial graphene p-n junctions
Dinesh Patel1,2*, Albert F. Rigosi1, Martina Marzano1,3, Mattias Kruskopf1,4,6, Chieh-I Liu1,5, Hanbyul Jin1,4, David B. Newell1, Randolph E. Elmquist1, Chi-Te Liang2
1Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
2Department of Physics, National Taiwan University, Taipei 10617, Taiwan
3Istituto Nazionale di Ricerca Metrologica, Torino 10135, Italy
4Joint Quantum Institute, University of Maryland, College Park, MD 20742, USA
5Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
6Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116-Braunschweig, Germany
* Presenter:Dinesh Patel, email:dkpjnp@gmail.com
We grew nearly homogeneous and monolayer epitaxial graphene (EG) on a hexagonal SiC substrate of centimeter-scale at 1850º C and developed a new technique to fabricate electrostatic-gate-free, monolayer EG based p-n junction devices. These devices were gated by static chemical doping, with designs including p-type and n-type regions in series and in 2x2 checkerboard patterns, using simple ultraviolet photolithography. This technique significantly reduces the device processing time compared to electron beam lithography and resulted in approximately 200 nm wide dissipation-free junctions. We performed the electromagnetic measurements of integer (1, 2, 3 …) and fractional (2/3, 8/7, 6/17, 12/13, 24/29, 32/57, and many more) multiples of the quantized Hall resistance in the ν=2 plateau (RH ≈12906 Ω) by applying single and multiple current injection points, respectively. Finally, we modeled all measured experimental data using an LTspice circuit simulator and predicted more complex embodiments of the quantum Hall resistance checkerboard. This new fabrication technique may be useful in resistance metrology for the scaling to different decade values of the electrical resistance measured in ohm.

Keywords: Quantum Hall effect, Epitaxial graphene, p-n junction, Integer and fraction multiple values of RH, Resistance metrology