Fig. 3: Carrier injection capability of the bottom MGr and WTe₂ contacts.

a Schematic and the transfer curves of MGr top-contacted FET. b Schematic and the transfer curves of WTe₂ top-contacted FET. c Schematic of and the transfer curves MGr bottom-contacted FET. d Schematic and the transfer curves of WTe₂ bottom-contacted FET. e, f Schematic of bottom-contacted WTe₂-WSe₂ and the network of contact resistances, and the corresponding schematic of the energy-band diagram. E_c, E_v, and E_s represent the energies of the conduction band, valence band and Fermi level in 2D semiconductor, respectively. E_m is the work function of the contact metal. SB represents the Schottky barrier. g, h Schematic of top-contacted WTe₂-WSe₂ and network of contact resistances, and the corresponding schematic of the energy-band diagram. i, j Schematic of MGr-WSe₂ and network of contact resistances, and the corresponding schematic of energy-band diagram. The dashed line in the energy-band diagram indicates the band evolution induced by V_g. Brown spheres: selenium atoms. Rose red spheres: tellurium atoms. Green and purple spheres: tungsten atoms. Gray spheres: carbon atoms. Regions A-D represent the metal contact, the interface gap, the contacted semiconductor, and the channel semiconductor region, respectively. ρsc is the sheet resistance of the semiconductor overlapped with the contact, r_c and r_e are the specific resistivities of the contact gap and edge, respectively, L_C is the contact length.