Regensburg 1998 – wissenschaftliches Programm

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HL: Halbleiterphysik

HL 2: Poster I

HL 2.107: Poster

Montag, 23. März 1998, 10:30–19:00, A

Electron-phonon interaction in a polar nanocrystal embedded into a polar matrix — •V. M. Fomin^1,2, S. N. Klimin¹, E. P. Pokatilov¹, and J. T. Devreese² — ¹Department of Theoretical Physics, State University of Moldova, Str. Mateevici 60, MD-2009 Kishinev, Republic of Moldova — ²Departement Natuurkunde, Universiteit Antwerpen (U.I.A.), Universiteitsplein 1, B-2610 Antwerpen, Belgium

A problem of the electron-phonon interaction in a polar nanocrystal embedded into a polar host, has become urgent due to the recent observation of the 1- and 2-photon absorption in CuCl/NaCl, CuCl/LiCl and ZnTe/LiCl quantum dot structures [1—3]. In the continuum approach, bulk-like and interface optical phonon modes are deduced for spherical nanocrystals and for those of the rectangular parallelepiped shape. The electron-phonon interaction with interface phonons in a cubic nanocrystal is stronger than in a spherical one of the same volume, due to the enhanced inhomogeneity of the electrostatic potential induced by the phonons near the edges and the corners. The dependence of the Fröhlich and deformational electron-phonon interaction amplitudes on the nanocrystal size and shape allows a consistent interpretation of the observed optical absorption and Raman spectra of nanocrystals. This work is supported by FWO-V, WOG and BOF NOI 97 (Belgium).

[1] D. Fröhlich et al., Solid State Commun. 94, 189 (1994)

[2] H.-J. Weber et al., Phys. Stat. Sol. (b) 191, 105 (1995)

[3] K. Reimann et al., Phys. Stat. Sol. (b) 198, 71 (1996)