Anéis quânticos: efeitos topológicos e de campo elétrico

• Ano de defesa: 1999
• Autor(a) principal: Lavenère-wanderley, Luiz Alberto Barreto
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Programa de Pós-graduação em Física; Física
• Palavras-chave em Português: Semicondutores de baixa dimensionalidade; Nanoestrutura; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
• Link de acesso: https://app.uff.br/riuff/handle/1/17357

Quantum rings can be viewed as a class of nanostructures which also presents quantum confinement effects leading to significant changes on optical and electronic properties. In particular, the electronic energy spectrum and wave functions of nanosystems are quite sensitive to electric fields due to the generated polarization of the spatial carrier distribution. These changes may be monitored to control and modulate output intensity of optoelectronic devices. In the present work, the polarization effects of an in-plane applied electric field on the physical properties of semiconductor quantum rings are discussed within the context of the effective-mass approximation. Electronic and hole states (ground and excited ones) of GaAs quantum rings of different electric field intensities. The effects of the annular topology of the quantum rings on the electronic properties are discussed and in particular we analyze the energy spectra of an electron in the conduction band and a hole in the valence band in the case in which the system does not present perfect symmetry, i. e., in in the case when the internal and external ring circles are not concentric. The dependence of the Stark shift of interband transitions on the electric fiend intensity is also presented.