Breaking the phonon bottleneck in semiconductor nanocrystals via multiphonon emission induced by intrinsic nonadiabatic interactions

• Published in: Physical review letters Vol. 95; no. 19; pp. 196401.1 - 196401.4
• Main Authors: SCHALLER, Richard D, PIETRYGA, Jeffrey M, GOUPALOV, Serguei V, PETRUSKA, Melissa A, IVANOV, Sergei A, KLIMOV, Victor I
• Format: Journal Article
• Language: English
• Published: Ridge, NY American Physical Society 04-11-2005
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Nanocrystals and nanoparticles; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; Excitons; Lead selenides; Semiconductor materials; Multi-phonon processes; Electron-phonon interactions; Absorption spectra; Intraband transitions; Nanocrystal; Cadmium selenides
• ISSN: 0031-9007; 1079-7114
• DOI: 10.1103/physrevlett.95.196401

We observe ultrafast 1P-to-1S intraband relaxation in PbSe and CdSe nanocrystals (NCs) that have distinct energy spectra. While ultrafast dynamics in CdSe NCs has typically been interpreted in terms of electron-hole energy transfer, this mechanism is not active in PbSe NCs because of sparse densities of states in the conduction and valence bands. Our observations of temperature activation and confinement-enhanced relaxation in PbSe NCs can be explained by efficient multiphonon emission triggered by nonadiabatic electron-phonon interactions and are indicative of large, size-dependent, intraband Huang-Rhys parameters.