Space-charge dynamics in a semiconductor nanoparticle and its potential for terahertz applications

Adjustable carrier concentration is an attractive feature of semiconductor nanoparticle that allows its surface plasmon resonance to be tuned. While quasi-static treatment of the electromagnetic interactions with the charge species can account for the polarization process in a conductive nanoparticle, a full-wave solution of the Maxwell´s equations is needed to give a realistic portrait of the current distribution when the nominal charge density exceeds 10²⁰cm^-3 in a typical nanoparticle. The analysis can be facilitated by the use of equivalent circuits, which readily give the induced dipole moment on a semiconductor nanoparticle in terms of material parameters and the radius of the particle. Prospects of semiconductor nanoparticles in terahertz technology are highlighted.