Interface and propagating optical phonon mixing modes in a wurtzite GaN-based quantum dot

摘要

The polar optical phonon vibrating modes of a quasi-zero-dimensional (Q0D) wurtzite cylindrical quantum dot (QD) are solved exactly based on the dielectric continuum model and Loudon's uniaxial crystal model. The result shows that there exist four types of polar mixing optical phonon modes in the Q0D wurtzite cylindrical QD systems, which is obviously different from the situation in blende cylindrical QDs. The dispersive equations for the interface-optical-propagating (10-PR) mixing modes are deduced and discussed. It is found that the dispersive frequency of 10-PR mixing modes in wurtzite QD just take a series of discrete values due to the three-dimensional confined properties. Moreover, once the radius or the height of the QD approach infinity, the dispersive equations of the 10-PR mixing modes in the wurtzite QOD cylindrical QD can naturally reduce to those of the 10 and PR modes in Q2D QWs or Q1D QWWs systems. This has been analyzed reasonably from both physical and mathematical viewpoints. The analytical expressions obtained in the paper are useful for further investigating phonon influence on physical properties of the wurtzite QOD QD systems. (c) 2006 Elsevier Ltd. All rights reserved.