Transport at Nanoscale Interfaces Laboratory

Joule-heating induced thermal voltages in graphene three-terminal nanojunctio

Pascal Butti, Rolf Brönnimann, Klaus Ensslin, Ivan Shorubalko; 

Appl. Phys. Lett. 112, 133501 (2018);
voltage rectification is investigated in a graphene three-terminal nanojunction (GTTJ) on Si/SiO2 at room temperature and 87 K. The room-temperature rectification efficiency (ratio of output against input voltage) reaches ≈40%, which is higher than most efficiencies reported in the literature. The observed efficiency is higher at room temperature than at 87 K, which is in contrast to field-effect simulations and indicates that other mechanisms contribute to the rectification effect. We propose an explanation based on Joule heating and thermal voltages, as the device is operated in regimes of substantial power dissipation. Predicted thermal voltages show temperature and bias- and gate-voltage dependences which are similar to those observed in our experiment. We conclude that Joule-heating effects need to be considered for GTTJ devices.