Chapter 15 - Phonons and Electron—Phonon Interactions in III-nitride Bulk and Dimensionally Confined Semiconductors and Their Device Implications

Abstract

This chapter examines fundamental properties of phonons in III-V nitrides with a view toward understanding processes important in the operation of III-V nitride devices. It describes confined, interface, and propagating modes in wurtzite quantum wells in terms of Loudon's model for uniaxial semiconductors and the dielectric continuum model. It discusses the basic properties of the phonon modes and carrier-phonon interactions on the basis of the treatment of dimensionally confined phonons in both bulk and low dimensional wurtzite structures. A key feature of these phonon modes is their enhanced dispersion and its origin from the non-isotropic nature of the wurtzites. There has been much interest recently on compound semiconductors formed of group III elements and nitrogen. They have significant potential for optoelectronic and electronic devices because of the interesting properties of this system, including the relatively large bandgap, the large piezoelectric field, the relatively strong electron-phonon coupling, and the relatively high polar-optical phonon energy. The phonons in the system of bulk materials as well as the lower dimensional structures are concentrated on in the chapter; moreover, the understanding of how these phonons behave in these structures and their impact in device applications are also focused in the chapter.