MoS2 Field-Effect Transistors With Graphene/Metal Heterocontacts

For the first time, n-type few-layer MoS2 field-effect transistors (FETs) with graphene/Ti as the heterocontacts have been fabricated, showing more than 160-mA/mm drain current at 1-mu m gate length with an ON-OFF current ratio of 10(7). The enhanced electrical characteristic is confirmed in a nearly 2.1 times improvement in ON-resistance and a 3.3 times improvement in contact resistance with heterocontacts compared with the MoS2 FETs without graphene contact layer. Temperature-dependent study on MoS2/graphene heterocontacts has been also performed, still unveiling its Schottky contact nature. Transfer length method and a devised I-V method have been introduced to study the contact resistance and Schottky barrier height in MoS2/graphene/metal heterocontacts structure.