Kinetics of free-exciton luminescence in GaAs

Abstract

Exciton-polariton photoluminescence kinetics under short-pulse excitation in nominally undoped GaAs has been investigated. A delayed onset revealing the energy relaxation of electrons and polaritons has been observed.In an ultrapure sample (No-IO' cm ) the maximum luminescence is

Thermodynamic origin of the slow free exciton photoluminescence rise in GaAs

“…1) is dominated by the free exciton recombination line (F X), which indicates a negligible density of impurity atoms in the active layer. From a comparison with spectra reported in the literature [10,24], we estimate a residual impurity concentration of 1 × 10 12 cm −3 . Polariton effects are neglected on the basis of the small L-T splitting in bulk FIG.…”

“…Time-resolved photoluminescence spectroscopy is widely used to investigate the kinetics of free exciton formation, relaxation, and recombination in semiconductors and their nanostructures [1]. In most experiments performed at low lattice temperatures a significantly delayed onset of the free exciton luminescence with respect to the excitation laser pulse is observed [2][3][4][5][6][7][8][9][10][11][12][13]. This slow photoluminescence (PL) rise has attracted intense research interest for nearly three decades.…”

Influence of trapping on the exciton dynamics of AlxGa1−xAs films

“…However, little attention has been paid to the luminescence dynamics of bulk GaAs, and even less to that of AlGaAs. Only recently some works, [2][3][4] which complement but not complete older scattered studies, [5][6][7][8] have investigated the emission dynamics just in GaAs, since good alloy samples have not been available. Yet, important issues in III-V alloys, such as the influence of defects or Aluminium content on the exciton dynamics, have not been addressed.…”

Exciton interaction with hot electrons in GaAs

“…10 Only a few experimental works address exciton creation in bulk GaAs. 11,12 From theory, we know no comprehensive model with quantitative agreement. Therefore, every additional experimental feature could contribute to the overall understanding.…”

“…This work was initiated by a luminescence-quenching effect, we investigated earlier, due to the interaction between hot electrons and free excitons in bulk undoped GaAs. 11 Excitons generated by previous laser excitations were destroyed or heated by the next ongoing laser pulse, causing luminescence quenching. The effect had a strong dependence on the excitation energy and power.…”