High Breakdown Current Density in Monolayer Nb₄C₃T_<i>x</i> MXene

MXenes are an emerging family of transition-metal carbides, nitrides, and carbonitrides that are promising for a variety of applications, including energy storage, gas sensors, and electromagnetic interference shielding. A recent report on a very high breakdown current density of ∼1.2 × 108 A cm–2 in Ti3C2Tx further extended the list of potential applications of MXenes to miniaturized on-chip interconnects. In this study, we investigated another promising member of the MXene family, Nb4C3Tx, and found that it also has a very high breakdown current density of ∼1.1 × 108 A cm–2, which is comparable to that of Ti3C2Tx and other highly conductive two-dimensional materials, such as graphene. The measurements were performed on electronic devices based on individual monolayer flakes of Nb4C3Tx, which were tested at gradually increasing voltages until the electrical breakdown was observed. The morphology of Nb4C3Tx devices after the breakdown was studied by microscopic techniques. The high breakdown current densities of Ti3C2Tx and Nb4C3Tx suggest that other members of the large MXene family likely possess this property and could be employed in applications utilizing their high current-carrying capacity.