Surface-plasmon-assisted electromagnetic field enhancement in semiconductor quantum dots |
| |
Authors: | Y Fu Y Zeng H Ågren |
| |
Institution: | (1) Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, 10691 Stockholm, Sweden |
| |
Abstract: | The temporal development of incident electromagnetic plane waves across semiconductor quantum dots (QDs) is analyzed by the
finite-difference time-domain method. By coating the QDs using thin metal films, surface plasmon polaritons (SPPs) can be
created. As illustration, our modeling approach is applied to fluorescent multiphoton quantum dots made of cadmium sulphide
of particular size (3.7 nm) and energy band gap (2.67 eV). When such a QD is coated by a metal film, a dipole-formed SPP is
generated at the external surface of the coated QD by the incident electromagnetic wave with a photon energy of 1.34 eV corresponding
to a two-photon process. When the thickness of the metal film is 0.37 nm, the peak intensity of the SPP oscillates through
both the thin metal film and the core QD, resulting in an electromagnetic field inside the QD enhanced by a factor of 10,
and thus an increased two-photon excitation that can be useful for bioimaging applications. Further increasing the metal film
thickness blockades the SPP initially generated at the external surface of the coated QD from penetrating through the metal
film, reducing the electromagnetic field inside the QD.
PACS 73.22.-f; 78.67.Hc |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|