Local field-induced optical properties of Ag-coated CdS quantum dots

Koo-Chul Je (1) , Honglyoul Ju (1) , Mona Tréguer-Delapierre (2) , Thierry Cardinal (2) , Seung-Han Park (1)

1 National Research Laboratory of Nonlinear Optics
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

Local field-induced optical properties of Ag-coated CdS quantum dot structures are investigated. We experimentally observe a clear exciton peak due to the quantum confinement effect in uncoated CdS quantum dots, and surface plasmon resonance and red-shifted exciton peak in Ag-coated CdS composite quantum dot structures. We have calculated the Stark shift of the exciton peak as a function of the local field for different silver thicknesses and various sizes of quantum dots based on the effective-mass Hamiltonian using the numerical-matrix-diagonalization method. Our theoretical calculations strongly indicate that the exciton peak is red-shifted in the metal-semiconductor composite quantum dots due to a strong local field, i.e., the quantum confined Stark effect.

Mots clés: Optics; Stark effect; Absorption spectroscopy; Semiconductors

Domaines: Matériaux; Optique [physics.optics]

Koo-Chul Je, Honglyoul Ju, Mona Tréguer-Delapierre, Thierry Cardinal, Seung-Han Park. Local field-induced optical properties of Ag-coated CdS quantum dots. Optics Express, 2006, 14 (17), pp.7994-8000. ⟨10.1364/OE.14.007994⟩. ⟨hal-00111137⟩