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.