Surface optical phonons in spherically capped quantum-dot/quantum-well heterostructures

Surface optical (SO) phonons are studied in the case of a spherical quantum-dot/quantum-well (QD/QW) heterostructure in the framework of a dielectric continuum approach. The prototypical case is a QD/QW of CdS/HgS in the form of a spherical shell of HgS sandwiched between a spherical core of CdS and a cap layer of CdS. Structures of this type appear to be of present interest to the scientific community and have been intensively investigated in the latter years. It is assumed that the QD/QW heterostructure is surrounded by a host material considered as an infinite dielectric medium which does not participate of the polar optical vibrations. We study the SO phonons, their frequency dependence on the geometrical and material parameters, as well as the electron-phonon interaction Hamiltonian. A detailed discussion of the SO phonons physical properties and of the electron-phonon interaction strength is also made. (C) 2003 American Institute of Physics.