Estudo de pontos quânticos auto-organizados de InAs por fotoluminescência

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

26/02/2010

RESUMO

Semiconductor structures with high confinement degree, such as quantum wells, quantum wires and quantum dots, have been of great interest, both from the technological point of view and for basic research. Self-Assembled Quantum Dots (SAQD`s) appear spontaneously, as a consequence of the lattice mismatch of the material deposited in relation to the substrate, when growing by Molecular Beam Epitaxy (MBE). In this work samples of Quantum Dots were studied by photoluminescence (PL) technique, with variation of temperature and excitation power. Samples of InAs SAQDs, grown on GaAs were studied. Dots within an InGaAs quantum well (14% of In) were also grown, and this kind of heterostructures are called DWELL (dots-in-a-well). The QDs structures were produced through continuous growth (with different deposition rates), as well as by pulsed growth, which consists of cycles of deposition and interruption interval. By analyzing the PL spectra was found that some samples of QDs exhibit an anomalous behavior with temperature of the energy of PL integrated intensity, and line width, wich can be explained considering the size distributions of the "dots". In two samples of QDs grown on GaAs, two PL peaks have been identified, whose behavior with temperature can be explained by considering a bimodal size distribution. For DWELL samples, one peak of PL has been identified, attributed to the emission of the ground state of QDs belonging to a continuous distribution of sizes.

ASSUNTO(S)

física da matéria condensada pontos quânticos fotoluminescência condensed matter quantum dots photoluminescence

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