July 9, 2018
      
                  
        
  Author(s)
  Jiuning  Hu,   Mattias  Kruskopf,   Yanfei  Yang,   Bi Y. Wu,   Jifa  Tian,   Alireza R. Panna,   Albert F. Rigosi,   Hsin Y. Lee,   George R. Jones Jr.,   Marlin E. Kraft,   Dean G. Jarrett,   Kenji  Watanabe,   Takashi  Taniguchi,   Randolph E. Elmquist,   David B. Newell
 
       
            
    
    
        We report the fabrication and measurement of top gated epitaxial graphene p-n junctions where exfoliated hexgonal boron nitride (hBN) is used as the gate dielectric. The four terminal longitudinal resistance across a single junction is well quantized at R_