Resistivity-controlled switching between photoemission and photothermoelectric effects in plasmonic nanojunctions

Nanoplasmonic optoelectronic devices exhibit ultrafast photoresponses through photothermoelectric and photoemission effects under femtosecond laser excitation, yet the interplay and transition between these mechanisms remain unexplored. Here, we modify the resistance between the two cathodes of nanojunctions by controlling the residual Ti adhesion layer. As the resistance increases, the primary mechanism of photocurrent generation shifts from photothermoelectric to photoemission.