Fig. 3: Contact resistivity analysis and benchmark of 1D semimetal contact.
From: One-dimensional semimetal contacts to two-dimensional semiconductors
a Top view and equivalent circuit of the MoS2 FET with 1D semimetal contact. Dotted boxes present the contact resistance between CNT and Ti (R1, yellow), the interconnect resistance of the CNT wire (R2, green) and the overall resistance of the heterostructure (R3, red). The white arrows represent the conduction current in channel. The W, L, and Lin are channel width, channel length and interconnect length of CNT wire. The shown resistance/resistivity quantities include the quantum resistance of CNT (\({R}_{{{{{{\rm{Q}}}}}}}^{{{{{{\rm{CNT}}}}}}}\)), the interfacial resistance between CNT and Ti (\({R}_{{{{{{{\rm{nc}}}}}}}}^{{{{{{{\rm{CNT}}}}}}}}\)), the resistivity of CNT wire (\({\rho }_{{{{{{\rm{CNT}}}}}}}^{{{{{{\rm{on}}}}}}\,{{{{{{\rm{Si}}}}}}}{{{{{{\rm{O}}}}}}}_{2}}\)), the resistivity of CNT electrodes in contact with MoS2 (\({\rho }_{{{{{{{\rm{CNT}}}}}}}}^{{{{{{{\rm{on}}}}}}}\,{{{{{{{\rm{MoS}}}}}}}}_{2}}\)), the 1D–2D interface contact resistivity (\({r}_{{{{{{\rm{c}}}}}}}\)), the sheet resistivity of MoS2 (\({\rho }_{{{{{{{\rm{TMD}}}}}}}}^{2{{{{{\rm{D}}}}}}}\)) and the equivalent resistance of the 1D–2D heterostructure (\({R}_{{{{{{\rm{H}}}}}}}\)). b Measured resistivity of the CNT with and without MoS2 contacting. The feature points β, X, DP and DP’ (marked by the vertical dashed lines) and the resulting five regions A-E are used for the CIFS analysis in Supplementary Note 4. c, Measured sheet resistivity of 1L and 4L MoS2. Inset is the interface resistance between CNT and Ti. d Extracted interface contact resistivity of the CNT/1L-MoS2 and CNT/4L-MoS2 heterojunction. Inset shows the band offset between different materials. e State-of-the-art contact technology for MoS2 transistors plotted as a function of contact length. The gray line represents the quantum limit of Rc with the carrier density n2D = 5 × 1012 cm−2. The polygons represent the data reported in experiments. The corresponding curves are theoretical deduction and the vertical dashed lines are transfer length for different contacts, they are all given by the Transmission Line Model (Supplementary Note 7). The blue shaded area indicates the area where the resistivity of conventional 3D/2D metal increases sharply due to the limitation of size effect. The solid red star represents the experimental measured data and the one with yellow core is the theoretical calculated result.
