Effect of Additional Illumination on the Kinetics of Exciton Complex Formation in the Quantum Wells of Undoped GaAs/AlGaAs Structures
RUSSIAN ACADEMY OF SCIENCES MOSCOW (RUSSIA) LEBEDEV INST
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Low-temperature T 2K photoluminescence PL and photoluminescence excitation PLE spectra of GaAs AlGaAs x 0.05 structures with shallow quantum wells QW and the effect of additional illumination by He-Ne laser radiation on these spectra were investigated. It was found that the PLE spectra exhibit a number of broad bands in the above-barrier energy region these bands alternate in opposite phases in the spectra of free excitons and excitonic complexes trions i.e., an increase in the exciton luminescence intensity is accompanied by a decrease in the luminescence intensity of the complexes. In the case where the photon energy of the Ti-sapphire laser is tuned to excite the QW states additional illumination results in the shift of the equilibrium in the exciton-trion system towards an increase in the concentration of the latter species. On the other hand upon excitation into certain barrier states with energy both below and above the barrier band gap additional illumination shifts the equilibrium in the opposite direction.
- Solid State Physics