Functionalized MoS₂ Nanoribbons for Intrinsic Cold-Source Transistors: A Computational Study

Power dissipation is a great challenge for continuous size scaling in CMOS technology because of the thermal limitation on the switching rate of conventional transistors. Here, to break the thermal tyranny, we propose a series of intrinsic cold-source field-effect transistors (CS-FETs) with steep slopes based on armchair transition-metal dichalcogenides (TMD) nanoribbons (NRs) (MX2NRs, M = Mo, W; X = S, Se, Te). The edge states of the TMD NRs can filter out the high-energy electrons and break the “Boltzmann tyranny” at room temperature. First-principles calculations unveil the electronic properties of −H, −F, and −H–O terminated MX2NRs with different ribbon widths. Based on quantum transport simulation, −F and −H–O terminated MoS2NRs present FET performance better than that of the −H terminated MoS2NR. A steep subthreshold swing (28 mV/decade) and a large ON/OFF ratio (4 × 105) are obtained for the 12-MoS2NR–F FET with a 5 nm channel length. Moreover, the effects of the ribbon width, channel length, bias voltage, edge roughness, and defects on MoS2NR–F FET performance are also investigated. This work demonstrates edge functionalization as an effective approach to modulate the TMD NRs and guides the design of intrinsic cold-source transistors.