Photon assisted tunnelling in single and coupled quantum dot systems

✍ Scribed by Toshimasa Fujisawa; Seigo Tarucha

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 216 KB
• Volume: 21
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1996.0191

✦ Synopsis

We describe photon assisted tunneling (PAT) in single and coupled quantum dot systems which have a relatively large zero-dimensional (0D) level separation. A microwave electric field applied across the tunneling barrier leads to the formation of a sideband structure. For a single quantum dot system, a PAT current peak is clearly observed in addition to the Coulomb oscillation peak. For a weakly-coupled double-dot system, we observe resonant 0D-0D PAT. The resonant PAT current appears only when two discrete quantum levels in the neighboring dots are exactly separated by the microwave photon energy. The PAT current shows a narrower peak than the main resonant tunneling current in accordance with time-dependent tunneling theory. The photon stimulated emission associated with PAT from a higher-lying occupied level to a lower-lying empty level is obtained at a drain voltage sufficient that population inversion takes place.