Münster 1999 – scientific programme
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HL: Halbleiterphysik
HL 23: Poster II
HL 23.10: Poster
Wednesday, March 24, 1999, 14:00–18:00, Z
Exciton recombination dynamics in GaAs/InGaP multiple quantum wells — •C. Rudamas and J. Martinez-Pastor — Departamento de Física Aplicada, Universidad de Valencia, C./ Dr. Moliner 50, 46100 Burjassot (Valencia), Spain
During the last years, a great deal of effort has been
placed on the study of the GaAs/InGaP system as an alternative to
GaAs/AlGaAs for the fabrication of electronic and optoelectronic
devices. The reasons are well understood, InGaP exhibits a much
lower concentration of deep levels than AlGaAs and
does not oxidize as readily as the latter.
In this work, the dynamics of the exciton decay
in GaAs/InxGa1−xP multiple quantum wells (MQWs) has been
studied by means of time resolved photoluminescence (TRPL)
as a function of the temperature, the well thickness and the
composition of the barriers.
The MQW samples were grown by atomic
layer molecular beam epitaxy. The In-content of the barriers
ranges between 0.43 and 0.54.
A monotonic decrease of the decay time with raising temperature is
experimentally observed, even at low temperatures.
This behavior, characteristic of the activation of
nonradiative recombination channels, could be attributed to interface
defects and compositional fluctuations in the MQWs studied here.
This is in agreement with results obtained from measurements of
similar kind of samples [1].
Small values of the valence band offset as well as a decrease of
them could also be deduced from the experimental results when the
In-content of the barriers is reduced. This is still in controversy
in the literature.
[1] J. Martínez-Pastor, L. González, G. Aragón, Ch. Guenaud and E. Delaporte, to be published in J. Appl. Phys., 84, Number 11 (1998)