Surface-plasmon-assisted electromagnetic field enhancement in semiconductor quantum dots
2007 (English)In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 87, no 2, 167-169 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2007. Vol. 87, no 2, 167-169 p.
Charged particles; Computer simulation; Electromagnetic fields; Electromagnetic waves; Surface plasmon resonance; Time domain analysis; Electromagnetic plane waves; Surface plasmon polaritons (SPP); Temporal development; Semiconductor quantum dots
IdentifiersURN: urn:nbn:se:kth:diva-7501DOI: 10.1007/s00339-006-3838-zISI: 000249502400006ScopusID: 2-s2.0-33947233980OAI: oai:DiVA.org:kth-7501DiVA: diva2:12546
QC 201008252007-09-252007-09-252010-08-25Bibliographically approved