Experimental PL spectra (close circles) and PR (open squares) at for the three SQWs in the energy range . Clear Franz-Keldysh oscillations above are displayed in the PR spectra. The least-squares fits to the first-derivative line shape functions are shown as solid curves. The obtained intersubband energies denoted as , respectively, for , , , , , , , , and transitions are marked by arrows below the features.
The PR spectra in the spectral range of excitonic transitions for (a) sample and (b) sample at 10, 30, 77, 100, 150, 200, 250, and . To facilitate comparison of spectra at different temperatures, a lateral shift of the spectra with respect to the transition is performed. The zero energy scale on the abscissa corresponds to the location of the transition. The obtained intersubband energies are denoted by letters and marked by arrows below the features.
Temperature dependence of the various excitonic transition energies for sample B. The solid and dotted lines are least squares fits to Eqs. (5) and (6), respectively. Representative error bars are shown for the experimental data.
The PL spectra of sample in the temperature range from 10 to . The PL peak positions as indicated by arrows are guides to the eyes.
The excitonic transition obtained from PR spectra and PL peak position of the three SQW samples in temperature range of . Representative error bars for the experimental data are indicated. The solid lines are least-squares fits to Eq. (5).
Temperature dependence of the broadening parameter evaluated from PR spectra with indicated error bars for the transitions for samples , , and . The solid lines are least-squares fits to Eq. (7).
The linewidth (FWHM) of the experimental PL peaks with indicated representative error bars for the three SQW structure in the temperature range of .
Summary of the three samples studied, showing value of the parameters , , and for Varshni coefficients, the parameters , and for Bose-Einstein coefficients, which describe the temperature dependence of the transitions of samples , , and .
Values of the parameters and which describe the temperature dependence of the broadening parameter of transition in and .
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