Estudo das estruturas de discordâncias cristalinas em arseneto de gálio
AUTOR(ES)
Alexandre Jose Medeiros do Nascimento
DATA DE PUBLICAÇÃO
2009
RESUMO
We employ ab initio calculations to investigate 90º partial dislocations in gallium arsenide. In a binary semiconductor like GaAs, two types of dislocations are present. In the a(ß) dislocation, there are two lines of arsenic (gallium) atoms on each side, bordering the geometric center of the dislocation core. For both the a ß and dislocations, we consider the energetics and electronic states of the quasi-fvefold (QF), the single- period (SP), and the double-period (DP) models that have been considered in the literature for 90.partials in semiconductors. In our calculations, we obtain the reconstruction energy, from the unreconstructed QF to the reconstructed SP, and the energy diference between the SP and DP cores, individually for each one of the a and ß dislocations. Given the presence of like-atom As-As (Ga-Ga) bonds along the core in the 90. a(ß)dislocation, in the QF, SP, and DP geometries, these are expected to be metallic, since As-As (Ga-Ga) bonds act as half-acceptors (half-donors) in GaAs. In view of that, we also consider antisite-doped models, in which one in every four As (Ga) atoms along the core of the a(ß)dislocation is replaced by a Ga (As) atom, in order to restore bond-stoichiometry in the core, in attempt to obtain semiconducting cores. The energetics of these bond-stoichiometric cores is compared with that of the QF, SP, and DP models.
ASSUNTO(S)
discordâncias cristalinas arseneto de gálio semicondutores binários física teses
ACESSO AO ARTIGO
http://hdl.handle.net/1843/ESCZ-7YSHACDocumentos Relacionados
- Estudos teóricos sobre discordâncias cristalinas em silício
- Controle de caos em amostras semi-isolantes de arseneto de gálio
- Difusão de enxofre em arseneto de galio por processamento termico rapido
- Influência do laser arseneto de gálio-alumínio em feridas cutâneas de ratos
- Laser de Arseneto de Gálio com alta energia não promove alteração colágena da matriz extracelular no músculo esquelético: estudo experimental