부산대학교 도서관

A graphene quantized Hall resistance (QHR) device fabricated at the National Institute of Standards and Technology, Gaithersburg, MD, USA, was measured alongside a GaAs QHR device fabricated by the National Research Council of Canada, Ottawa, ON, Canada, by comparing them to a 1- $\text{k}\Omega $ standard resistor using a cryogenic current comparator. The two devices were mounted in a custom developed dual probe that was then assessed for its viability as a suitable apparatus for precision measurements. The charge carrier density of the graphene device exhibited controllable tunability when annealed after Cr(CO) 3 functionalization. These initial measurement results suggest that making resistance comparisons is possible with a single- probe wired for two types of quantum standards—GaAs, the established material, and graphene - the newer material that may promote the development of more user-friendly equipment.