Quantum Hall Transport Measurements of Lateral p-n Junctions Formed via Precise Spatial Photodoping of Graphene/hBN Heterostructures

Published

March 24, 2024

Author(s)

Angela Hight Walker, Thuc Mai, Maria Munoz, Curt Richter

Abstract

We spatially dope heterostructures composed of 2-dimensional (2D) materials to modify devices in-operando for custom functionalities, such as lateral p-n-p junctions. After optically photodoping an hBN/Graphene/hBN heterostructure, we measure the detailed magnetotransport including quantum Hall transport and observe several clear electronic regimes. In the p+-p-p+ and n-n+-n configurations, we see clear quantization of the longitudinal resistance. Using the Landauer-Buttiker model we elucidate the nature of the electrostatic profile at the interface between the doped regions. In the p-n-p configuration, due to the heavily graded junction profile that completely separate the p- and n-Landau level edge states from interacting, we create an "insulating" state that is not common and has not been observed in previous quantum Hall transport measurements of graphene pnJ devices in high magnetic fields. This insulating state could be the basis for a high-performance graphene switching device with a good ON/OFF ratio. In principle, these doping and measurement techniques can be applied to any other 2D heterostructure encapsulated within an hBN sandwich to understand the quality of the electrostatic interface between doped regions.

Citation

ACS Nano

Pub Type

Journals

Keywords

graphene, quantum Hall, photodoping, Hall bar, magneto-transport

Citation

Hight Walker, A. , Mai, T. , Munoz, M. and Richter, C. (2024), Quantum Hall Transport Measurements of Lateral p-n Junctions Formed via Precise Spatial Photodoping of Graphene/hBN Heterostructures, ACS Nano (Accessed January 13, 2025)