The modulation of Schottky contacts of p-type graphene-GeC/GeS heterointerface Honglin Li, Yuting Cui and Haijun Luo Eur. Phys. J. Appl. Phys., 84 3 (2018) 30101 Published online: 14 January 2019 DOI: 10.1051/epjap/2018180279