Indirect Observation Of The Light Emission In The Tunnel Junction With Metal Nanodisk

This work is devoted to the study of plasmonic properties of electrically driven gold nanodisks employing scanning tunnel microscopy induced luminescence (STML). Gold disks were fabricated with the use of e-beam lithography. The size of the disks (diameter of 120-180 nm and height of 60 nm) was comparable with the wavelength emitted. To confirm that the observed emission of photons is associated with inelastic tunneling of electrons, but not with the collision of the probe with the nanodisk surface, the nanodisk was STML scanned at different angles of the probe motion (0, 90, 270 degrees). In all cases the obtained images were identical. It was shown that nanodisk provided nonuniform STML map, the edges of the nanodisk emitted light with higher intensity compared to the center. Also, current-voltage I(V) characteristics at different points of a nanodisk were obtained and analyzed, and the acquired features at I(V) curves were correlated to the STML results. The proposed approach based on I(V) curves analyzing is very promising for the indirect study of optical properties of the electrically driven nanoscale photon sources.