* Corresponding author. Tel.: #49-931-888-6330; fax: #49- 931-888-6332. E-mail address: wolfgang.kiefer@mail.uni-wuerzburg.de (W. Kiefer). Journal of Crystal Growth 214/215 (2000) 792}796 Resonance Raman spectroscopy and excitation pro"le of Cd  Zn  Se/ZnSe quantum wires B. Schreder, T. Ku K mmell, G. Bacher, A. Forchel, G. Landwehr, A. Materny, W. Kiefer* Institut fu ( r Physikalische Chemie der Universita ( t Wu ( rzburg, Am Hubland, D-97074 Wu ( rzburg, Germany Physikalisches Institut der Universita ( t Wu ( rzburg, Am Hubland, D-97074 Wu ( rzburg, Germany Abstract We present resonance Raman spectra obtained from CdZnSe/ZnSe quantum wires and short wires with di!erent wire lengths and widths and cadmium contents of 20%. The spectra show high outgoing resonances for the LO overtones (2LO and 3LO). For two wire sizes ((a): length ¸"100 m, width ="18 nm; (b): ¸"49 nm, ="27 nm) excitation pro"les of the LO fundamental and of the "rst overtone of Cd  Zn  Se quantum wires have been recorded. The excitation pro"les clearly show structures attributed to the incoming and outgoing resonances. Furthermore, both luminescence intensity and the intensity ratio 2LO/1LO show a decrease with increasing sample age due to aging e!ects, whereas the phonon wavenumber positions are not a!ected by the sample age.  2000 Elsevier Science B.V. All rights reserved. PACS: 78.30.F Keywords: Raman scattering; Resonance Raman spectroscopy; CdZnSe/ZnSe; Excitation pro"le; Quantum wires 1. Introduction In the last years, the electron}phonon coupling, which describes the interaction between the optical excited carriers with the lattice vibrations in semi- conductors, has been the subject of many theoret- ical and experimental investigations. For example the Raman signals of the optical phonons show a strong increase in intensity when the energy of the exciting laser light (incoming resonance) or of the scattered light (outgoing resonance) matches the energy of an electronic transition. In the case of the polar II}VI-semiconductors the coupling due to the Fro K hlich mechanism [1,2] is found to be the main mechanism for the coupling of carriers with LO phonons, whereas the deformation poten- tial coupling plays only a minor role [3]. An experi- mental method to obtain the coupling strength and its size and excitation wavelength dependence is given for example by Raman spectroscopy. The intensity ratio of the overtones to the LO funda- mental can be used as a direct measure for the coupling strength [4}10]. 0022-0248/00/$ - see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S 0 0 2 2 - 0 2 4 8 ( 0 0 ) 0 0 2 3 4 - 7