Detalhes bibliográficos
| Resumo: | Employing a low-temperature growth-mode, we fabricated ultrathin Si1-xGex/Si multiple quantum well (QW) structures with a well thickness of less than 1.5 nm and a Ge concentration above 60 % directly on a Si substrate. We identified an unusual temperature-dependent blueshift of the photoluminescence (PL) and an exceptionally low thermal quenching. We find that this behavior is related to the relative intensities of the no-phonon (NP) peak and a phonon-assisted replica that are the main contributors to the total PL signal. In order to investigate these aspects in more detail, we developed a strategy to calculate the PL spectrum employing a self-consistent multi-valley effective mass model in combination with second-order perturbation theory. According to our investigation, we find that while the phonon-assisted feature decreases with temperature, the NP feature shows a strong increase in the recombination rate. Besides leading to the observed robustness against thermal quenching, this causes the observed blueshift of the total PL signal. |
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| Autores principais: | Wendav, T. |
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| Outros Autores: | Fischer, I. A.; Virgilio, M.; Capellini, G.; Oliveira, F.; Cerqueira, M. F.; Benedetti, A.; Chiussi, S.; Zaumseil, P.; Schwartz, B.; Busch, K.; Schulze, J. |
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| Assunto: | Photoluminescence Ge quantum wells |
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| Ano: | 2016 |
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| País: | Portugal |
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| Tipo de documento: | artigo |
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| Tipo de acesso: | acesso aberto |
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| Instituição associada: | Universidade do Minho |
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| Idioma: | inglês |
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| Origem: | RepositóriUM - Universidade do Minho |
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