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Photoluminescence spectra of samples A–D measured at . The inset shows the measured (dots) and calculated (solid line) PL peak energies as a function of the well width.
Time-resolved photoluminescence spectra of samples A (a), B (b), C (c), and D (d) measured at different temperatures. The solid line shown in (a) is the measured laser line.
Measured (dots) and fitted (solid lines) temperature dependences of the PL decay times of samples A–D. The fitting curves were calculated according to Eq. (7) by considering for radiative recombination and Eq. (6) for nonradiative recombination.
relationship of samples C and D.
The factor as a function of the well width, where is proportional to the defect density .
Measured (dots) and fitted (solid lines) temperature dependences of the integrated PL intensities of samples A–D. The solid curves were fitted according to Eq. (10) while the parameters in Table I were used. The laser powers used for excitation are for samples A and B, for sample C, and for sample D.
Measured MPE activation energies as a function of the quantization energy in the investigated multi-quantum-wells (dots) and the fitting result (solid line) according to Eq. (11).
Parameters for samples A–D: well widths, PL peak wavelengths, center wavelengths of bandpass filters used for t-PL experiments, factors, factors, and the activation energies obtained from the linear relationships in high temperature range defined by Eq. (3) and from best fitting of the whole curves defined by Eq. (7). The values in parentheses were obtained by fitting temperature dependence of integrated PL intensity according to Eq. (10). These values are less reliable because of the weak nonradiative process in sample A and weak radiative process in sample C.
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