Giant Low Temperature Heat Capacity of GaAs Quantum Wells near Landau Level Fillingν=1

Effects of low-temperature capping on the optical properties of GaAs/AlGaAs quantum wells

We study the effects of low-temperature capping (200-450°C) on the optical properties of GaAs/AlGaAs quantum wells. Photoluminescence measurements clearly show the formation of abundant nonradiative recombination centers in an AlGaAs capping layer grown at 200°C, while there is a slight degradation of the optical quality in AlGaAs capping layers grown at temperatures above 350°C compared to tha...

Room temperature spin diffusion in (110) GaAs/AlGaAs quantum wells

Transient spin grating experiments are used to investigate the electron spin diffusion in intrinsic (110) GaAs/AlGaAs multiple quantum well at room temperature. The measured spin diffusion length of optically excited electrons is about 4 μm at low spin density. Increasing the carrier density yields both a decrease of the spin relaxation time and the spin diffusion coefficient Ds.

Photoluminescence Upconversion in GaAs Quantum Wells

We present a detailed experimental study of photoluminescence upconversion in GaAs quantum wells over a wide temperature range. The dependence of the upconversion on the well width is discussed and the conversion efficiency is determined as a function of laser detuning. The best results are achieved when the laser detuning is comparable to the thermal energy of the system, ∆E ≈ 2kBT .

Spin relaxation in GaAs(110) quantum wells

Charged exciton dynamics in GaAs quantum wells

We study the dynamics of the charged and neutral excitons in a modulation-doped GaAs quantum well by time-resolved photoluminescence under a resonant excitation. The radiative lifetime of the charged exciton is found to be surprisingly short, 60 ps. This time is temperature independent between 2 and 10 K, and increases by a factor of 2 at 6 T. We discuss our findings in view of present theories...