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Understanding the physics of Ini..GaAsPi multiple quantum well (MQW)
nanostructures is essential for the development of new photonic devices such as lasers,
amplifiers and modulators. In this work, optical and structural properties as well as
vertical transport of three different heterostructures grown by metalorganic vapor phase
epitaxy and emitting at 1 .33 tm and 1 .55 jim have been studied using continuous wave
and time-resolved photoluminescence (cw-PL and TRPL) and high resolution x-ray
diffraction (HRXRD). Cw-PL measurements show an anomalous PL characteristics for
the structure with a thicker active layer which is discussed in terms of electron-acceptor
transitions, donor-acceptor pairs, and constraint relaxation and related structural defects.
The overall observed red shift with increasing temperature is interpreted as resulting
from two opposite and competitive processes: band-gap shrinkage (dominant) and blue
shi:ft caused by fluctuations in the QW layer thickness across the lateral sample
direction. In the observed full width at half maximum, we identified a component of 8
meV as a contribution from longitudinal optical phonons. At high excitation densities, it
is shown that carrier spillover and Auger recombination may be the major mechanisms
limiting the quantum efficiency. For TRPL measurements, carrier cooling rates are
discussed in terms of concurrent and opposite scattering mechanisms. It is found that
the rise times of the QWs and the confinement region increase slightly (''2 ps) on
decreasing the excitation wavelength. The observed difference is attributed to a higher
initial carrier temperature associated with the shorter excitation wavelength.
Comparable times of 4 ps are observed for the carrier transport and relaxation time
within the confinement region and the carrier capture time in the quantum wells.
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