Estudio de la fotoluminiscencia de pozos cuánticos de Ga1−xInxNyAs1−y/GaAs
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Segura Ruiz, Jaime A. | 2008-11-19
In the last years, nitride III-V semiconductor alloys attract an increasing amount of attention due to their interesting optical properties and the related potencial for applications in various electronic and optoelectronic devices. The diluted quaternary alloy Ga1−xInxNyAs1−y is a promising material in the field of optical communications, expecting to provide efficient light emitters at the 1.3 and 1.55 μm low
loss bands, and being lattice-matched to GaAs, which is desirable because allows to use the technology developed for this binary compound. It is known that N incorporation degrades the optical properties of diluted nitride semiconductor, due to an increasing density of non-radiative centers. In order to remove such defects,
post-growth thermal annealing of the sample is necessary. The optical properties of Ga1−xInxNyAs1−y improve considerably after annealing but this also causes a large blueshift of the emission.
In this work, we will study by photoluminescence, the optical properties of Ga1−xInxNyAs1−y/GaAs single quantum wells, and the effect of post growth rapid thermal annealing in these properties. The studied samples are 7 nm-thick single quantum wells with y = 0.015 and x varying between 0.2 and 0.3 which undergo
post growth rapid thermal annealing at 850 C for 15”. One of this samples also incorporates a GaInAs quantum well with identical In-concentration as the Ga1−xInxNyAs1−y. The photoluminescence (PL) of as-grown and annealed samples, measured as a function of temperature and excitation density, show that Ninduced localized states dominate the emission spectra at low temperature. The localization potential was calculated from the low energy tail of the emission, showing
that thermal annealing reduces the localization grade in all these samples.
In order to clarify the nature of low temperature emission, PL measurements as a function of the excitation power and under a magnetic field have been carried out. These results confirm that low temperature recombination is not excitonic and involves localized electrons and free holes.
LEER