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Characterization of the QW wire sample. (a) Scanning electron microscope image at a cleaved cross section. (b) Potential of the QW wire structure as modeled by the finite element method within the framework of elasticity theory. The inset shows a level scheme illustrating recombination processes from the QW (index 1) and wire regions (index 2) as well as the carrier transfer from the QWs to the wires (index ), without taking into account the details of the semiconductor band structure.
Streak-camera images of the PL data from the unpatterned reference QW (a) and from the QW-wire sample (b) for an excitation flux per pulse of . (c) PL spectra for increasing excitation flux per pulse taken at , i.e., after most of the lateral transport took place. The reference spectrum at (bottom) is representative for the initial population. In all cases is set to the maximum of the excitation pulse as imaged by the detection system.
PL transients from the QW wire sample. Full circles represent PL data from the QW, whereas open circles indicate data that stem from the wire PL. The excitation pulse, as imaged by the complete detection system (apparatus function) is given as a dashed line. The excitation flux per pulse in (a), (b), and (c) is , , and , respectively. The full lines in (c) represent a normalized fit according Eqs. (1) with initial populations of and as well as time constants , , , and a delay time of 27 ps. The numbers given in the figure represent the time constants ( decay) as determined from the slopes of the respective data.
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