PRESSURE-TUNED AND LASER-TUNED RAMAN-SCATTERING IN II-VI SEMICONDUCTOR NANOCRYSTALS - ELECTRON-PHONON COUPLING

We report pressure- and laser-tuned Raman-scattering studies on CdSxSe1-x nanocrystals. The electron-phonon coupling strength S, known as the Huang-Rhys parameter, was determined as a function of pressure beyond the bulk-phase-transition pressure point. The coupling strength is not drastically smaller, as might be expected theoretically, and also shows no abrupt changes at the bulk-phase-transition pressure point. These results indicate that deep traps play a critical part in the mechanism of the electron-phonon coupling. © 1994 The American Physical Society.