▎ 摘　　要

We report on the fabrication and characterization of high quality graphene p-n-p junctions encapsulated by hexagonal boron nitride. By tuning the back gate and top gate bias voltages, a graphene p-n-p junction with tunable polarity and doping levels was realized. The p-n-p junction displayed distinct resistance oscillations, which was attributed to the Fabry-Perot interference of charge carriers in the p-n-p cavity. When a small magnetic field was applied, the oscillation phase was shifted by pi, indicating the observation of Klein tunneling of charge carriers in the p-n-p junctions. The observation of Fabry-Perot interference and Klein tunneling with a macroscopic cavity length of L-c = 500nm demonstrates the markedly high quality of our graphene p-n-p junction. (C) 2013 The Japan Society of Applied Physics