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Proceedings Paper

Electron and hole dynamics in GaSe nanoparticles and GaSe-InSe nanoparticle heterojunctions
Author(s): David F. Kelley; Haohua Tu; Karoly Mogyorosi; Xiang-Bai Chen
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Paper Abstract

Femtosecond polarized transient absorption results are obtained for InSe and GaSe nanoparticles. The results indicate that the transient absorption spectrum of large GaSe particles is dominated by a size-independent, z-polarized hole intraband transition. The small particle spectra exhibit the same z-polarized hole transition and a much more intense x,y-polarized absorption that is assigned to a charge transfer transition from the conduction band to particle surface (edge) states. The intensity of this transition depends on the momentum state (Γ or M) of the electron, and Γ to M electron momentum relaxation results in a 15 ps absorption decay. These results are used to interpret analogous results obtained for mixed GaSe-InSe nanoparticle aggregates, also in the solution phase. The static absorption spectrum of the mixed aggregates exhibits a strong interparticle charge transfer absorption band at an energy slightly higher than the InSe bandgap. Photoexcitation of this band results in a polarized transient absorption spectrum and transient absorption kinetics characteristic of InSe valence band holes and GaSe conduction band electrons. This result indicates that with small GaSe particles, direct InSe to GaSe electron transfer occurs upon photoexcitation.

Paper Details

Date Published: 30 August 2006
PDF: 7 pages
Proc. SPIE 6325, Physical Chemistry of Interfaces and Nanomaterials V, 63250F (30 August 2006); doi: 10.1117/12.680083
Show Author Affiliations
David F. Kelley, Univ. of California, Merced (United States)
Haohua Tu, Univ. of California, Merced (United States)
Karoly Mogyorosi, Univ. of California, Merced (United States)
Xiang-Bai Chen, Univ. of California, Merced (United States)

Published in SPIE Proceedings Vol. 6325:
Physical Chemistry of Interfaces and Nanomaterials V
Mark Spitler; Frank Willig, Editor(s)

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