Fig. 5. Device-to-device variation in field-effect mobility and contact resistance.

Distribution of mobility extracted using peak transconductance (${\mu }_{g_{\mathrm{m}}}$) for different channel lengths for a MoS₂ and b WS₂ FETs. Median, 25th percentile, and 75th percentile is also denoted. Total resistance (R_T) versus L_CH for c MoS₂ and d WS₂ for different carrier concentrations (n_S) extracted using a representative TLM structure. The distribution of contact resistance (R_c) across multiple TLM structures, extracted from the y-intercepts in c and d, as a function of n_S for e MoS₂ and f WS₂, respectively. The relative contribution of R_c and channel resistance (R_ch) to the total resistance for g MoS₂ and h WS₂ for different L_CH. In scaled devices, as R_ch scales with the channel length, the contribution of R_c (note that R_c is independent of L_CH), i.e., 2R_c/R_T, is more significant compared to R_ch, i.e., R_ch/R_T.