the supplementary material for the detailed sample preparation, schematic of transfer process, optical and Raman characterization, transport properties of NbxMo1−xS2 and MoS2, diode properties of NbxMo1−xS2/MoS2, transport properties of another NbxMo1−xS2/MoS2 device, transport properties of NbxMo1−xS2/MoS2 vertical heterostructure.