Confinamento de fónons ópticos em estruturas piezoelétricas periódicas e quasiperiódicas

AUTOR(ES)

Paulo Dantas Sesion Júnior

DATA DE PUBLICAÇÃO

2005

RESUMO

We study the optical-phonon spectra in periodic and quasiperiodic (Fibonacci type) superlattices made up from III-V nitride materials (GaN and AlN) intercalated by a dielectric material (silica - SiO2). Due to the misalignments between the silica and the GaN, AlN layers that can lead to threading dislocation of densities as high as 1010 cm−1, and a significant lattice mismatch (_ 14%), the phonon dynamics is described by a coupled elastic and electromagnetic equations beyond the continuum dielectric model, stressing the importance of the piezoelectric polarization field in a strained condition. We use a transfer-matrix treatment to simplify the algebra, which would be otherwise quite complicated, allowing a neat analytical expressions for the phonon dispersion relation. Furthermore, a quantitative analysis of the localization and magnitude of the allowed band widths in the optical phonons spectra, as well as their scale law are presented and discussed

ASSUNTO(S)

semicondutores periodical structures estruturas quasi-periódicas fisica phonons nitretos nitride quasiperiodic structures saemiconductors estruturas periódicas fónons optical-phonon fónons ópticos

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