Tunable Charge Transfer Plasmon
Nordlander, Peter J.
Doctor of Philosophy
Both bonding dipolar mode (BDP) and charge transfer plasmon (CTP) is observed when two metallic nanoparticles are linked by conductive junction. This thesis investigates optical properties of CTP, and demonstrated that CTP, as a result of charge transfer through conductive junction, is very sensitive to junction geometry and junction conductance. This thesis systematically studied resonance energies, scattering intensities and linewidths of CTPs and BDPs supported by linked pairs of nanoparticles. The most important finding of their spectral dependence on conductance is: decreasing the junction conductance shifts CTP resonance to lower energy to the near-infrared (NIR) or mid-infrared (MIR) spectral region. Therefore, we find a novel approach to control plasmon modes at infrared wavelengths: tune CTP by changing junction properties. At the same time, CTP can be used to measure the electrical transport properties of nanomaterials at optical frequencies when they are placed in the junction.
charge transfer plasmon; infrared; electrical transport properties; AC conductance