|
|||||
|
|
Exchange interaction and acoustical phonon modes in CdTe nanocrystals |
|
| Authors: | P Lavallard M ChamarroJ Pérez-Conde AK BhattacharjeeSV Goupalov AA Lipovskii |
| Institution: | a Groupe de Physique des Solides, Universités Paris 6 et 7, UMR 7588 du CNRS, 2 place Jussieu, 75251 Paris, France b Departamento de Fisica, Universidad Publica de Navarra, E-31006 Pamplona, Spain c Laboratoire de Physique des Solides, UMR du CNRS, Université Paris-Sud, 91405 Orsay, France d School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30002-0250, USA e A.F. Ioffe Physico-Technical Institute, Russian academy of Sciences; 26 Polytechnicheskaya, 194021 St Petersburg, Russia f St Petersburg State Technical University, Polytechnicheskaja 29, St Petersburg 19251, Russia |
| Abstract: | Photoluminescence of CdTe nanocrystals (NC) is excited resonantly in the lowest energy absorption peak. The spectrum shows a luminescence line shifted to a lower energy and acoustical and optical phonon replica. The Stokes shift between the luminescence and excitation lines is attributed to the electron-hole exchange energy in the nanocrystal. By tuning the laser line inside the absorption peak, we are able to measure the Stokes shift as a function of the excitation energy. Calculation of the absorption gap and the Stokes shift is done in a tight-binding theory. It allows us to determine the radius R of NC excited at a given wavelength and to compare the experimental and theoretical values of the exchange energy as a function of R. A very good agreement is obtained. The observed size dependence of the acoustical phonon mode energy provides a further confirmation of our analysis. |
| Keywords: | 71 35Cc 78 55 Et 78 67 Bf 81 07 Bc |
| 本文献已被 ScienceDirect 等数据库收录！ | |