Fermi level de-pinning by using one-dimensional edge contact to MoS2

Electrical metal contacts to two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDCs) are considered as a main obstacle to the device performance due to high contact resistance and uncontrollable Schottky barrier heights (SBH), indicating strong Fermi level pinning. Here, we fabricate one-dimensional edge contact to MoS₂ covered with h-BN by using plasma etching technique. The pinning factor S for MoS₂ contacted to metal via edge increases from 0.1 to 0.3, but still shows strong pinning due to large band gap of thin MoS₂. However, edge contact to bulk MoS₂ with high work function metal Pd shows ambipolar behavior, indicating clear de-pinning effect. Additionally, we compare transport mechanism between surface and edge contacts without h-BN. Based on these differences, we accomplished rectifying junction with heterogeneous contact structure.