Excitation energy dependence of the optical properties of InGaAs/GaAs quantum well heterostructures

Il Nuovo Cimento D - We report an experimental study on a large set of InGaAs/GaAs quantum well structures by means of continuous-wave photoluminescence and photoluminescence excitation. The...     

Resonant rayleigh scattering in semiconductor structures

Il Nuovo Cimento D - A detailed study of the relative role played by localized and/or propagating intermediate excitonic states in, resonant Rayleigh scattering (RRS) is presented for a large set...     

Carrier recombination kinetics in (3 1 1)A InGaAs sidewall quantum wires

We present a study of the optical properties and carrier dynamics in strained InGaAs sidewall quantum wires (QWR) on patterned GaAs (3 1 1)A substrates by means of picosecond time-resolved photoluminescence (PL). A pronounced dynamical red shift of the QWR-PL band when increasing the delay time after the pulse excitation is observed. In addition, time-resolved data show a significant shortening of the PL decay time from the wire at short delay and when high excitation power is used. The data are compared with theoretical predictions. The results, i.e. the dynamical red shift observed in the wire emission and the shortening of the PL decay with increasing the excitation density, are interpreted in terms of a dynamical screening effect of the piezoelectric field.     

Acoustic phonon dephasing in shallow GaAs/Ga Al As single quantum wells

The intermediate dimensionality regime is studied on a set of shallow GaAs/Ga Al As single quantum wells. Such heterostructures exhibit 2D strong excitonic electroabsorption together with near 3D fast transport properties. We report dephasing time measurements of the heavy-hole exciton and we show that the acoustic phonon contribution decreases with to a value in good agreement with theoretical predictions for GaAs bulk.     

Ultra-large tuning of photonic modes for efficient Er-doped silicon-based emitters

We demonstrate that a gentle gas adsorption technique can be used to achieve an optimal covering of silicon-based photonic crystal slabs, leading to an unexpectedly large (up to 42 nm) shift of the resonant modes wavelength, with possibility of fine tuning. Strong enhancement (up to 30 times) of the emission band of the Er³⁺ ion into such structures is obtained. Finally, we were able to balance the adsorption and desorption processes by controlling the sample temperature, thus yielding a stable mode at the desired wavelength.     

Meson exchange effects in thermal n-p radiative capture

It is shown that the meson exchange contributions to the n-p radiative capture matrix element are nearly independent from the nucleon-nucleon potential model. The resulting interaction effect, including the N₃₃¹ contribution calculated by Stranahan, is ～ 9%.