Graphene-Integrated Negative Quantum Capacitance Field-Effect Transistor With Sub-60-mV/dec Switching

The aggressive scaling of metal-oxide- semiconductor field-effect transistor (MOSFET) has urged advanced device technology overcoming the 60-mV/dec limit of subthreshold slope (SS) at room temperature. The introduction of a negative component in the FET gate capacitance has been proven effective to realize steep-slope switching. Here, we report a sub-60-mV/dec MoS2 negative quantum capacitance FET (NQCFET) with single-layer (SL) graphene integrated in the gate-stack. The negative quantum capacitance from the low density of states (DOS) is strongly associated with the electron system of the 2-D SL graphene. With this negative contribution to the gate capacitance, subthermionic switching is achieved in the NQCFET with a minimum SS of 31 mV/dec. This prototype device illustrates a feasible approach to realize negative quantum capacitance in an FET architecture and opens attractive pathways for future steep-slope and low-power electronic device applications.