Communications in Physics, Vol. 24, No. 4 (2014), pp. 333-342 DOI:10.15625/0868-3166/24/4/3268 OPTICAL PHONON MODES AND ELECTRON–OPTICAL PHONON INTERACTION IN CORE-SHELL SEMICONDUCTOR QUANTUM WIRES NGUYEN NHU DAT Institute of Physics, Vietnam Academy of Science and Technology and Duy Tan University, Da Nang, Vietnam LE THANH HAI Hanoi University of Civil Engineering, Vietnam E-mail: nndat@iop.vast.ac.vn Received 19 June 2014 Accepted for publication 12 November 2014 Abstract. Within the framework of the macroscopic dielectric continuum model the longitudinal optical (LO) phonon modes are derived for a cylindrical semiconductor quantum wire made of semiconductor 1 (well material) embedded in another finite semiconductor 2 (barrier material). The phonon states of modes are given by solving the generalized Born-Huang equation. It is shown that there may exist four types of longitudinal optical phonon modes according to the concrete materials forming the wire. The dispersion equations for phonon frequencies with wave-vector components parallel to the wire are obtained. After having quantized the phonon field we derive the Fr¨ ohlich Hamiltonian describing the electron–LO-phonon interaction. The influence of the thickness of the barrier layer as well as the thin metallic shell on the phonon frequencies and their interaction with electrons is studied. Keywords: core-shell wire, thickness, phonon, dispersion. I. INTRODUCTION The progress in semiconductor nanotechnology has made it possible to fabricate quasi- one-dimensional wire structures of different semiconductor materials. These semiconductor wire structures have lateral dimension small relative to the electron thermal de Broglie wavelength and, therefore, exhibit a number of new, so-called quantum size effects which make the structures attract much attention due to their potential technological application [1–9]. The electron-phonon interaction in semiconducting low-dimensional systems in general, and in one-dimensional quantum wires in particular, is of great importance since it is one of the main mechanisms that govern carrier relaxation in transport phenomena. In the past, sev- eral workers [10–15] had carried out studies of the electron interaction with longitudinal optical (LO) phonons in quantum wires considering the modification of the electron energy spectrum and wave function due to their space localization but assuming the bulk forms for LO phonon modes. c 2014 Vietnam Academy of Science and Technology