Potential profile for the interdiffusion of an quantum well structure at (a) , (b) , (c) , and (d) .
X-ray diffraction measurements for superlattice sample 1 (a) as-grown and postannealed at 848 K for (b) 1250 s and (c) 5000 s.
Photoluminescence spectra at 77 K for (a) sample 1 and (b) sample 3 consisting of AlSb barriers and GaSb wells, before and after annealing at 908 K for 125 s.
Expected PL energies as a function of , calculated as shown in Eq. (8) using confinement energies from model 1. Expected PL energies were evaluated considering heavy holes and light holes for the calculation of the valence-band confinement energies. Also, the expected quantum well band gap, , is plotted as a dotted line.
Energy shifts in photoluminescence spectra after annealing at 948 K (◆), 908 K (●), 873 K (∎), and 848 K (▴) at selected time periods.
Calculated confinement energies for electrons , light holes , and heavy holes as a function of determined using model 1.
Experimental and calculated energy shifts as a function of . The calculated energy shifts were determined by subtracting the expected PL energy for an unannealed sample (at , determined using the Kronig–Penney model) from the expected PL energy calculated using model 1.
Arrhenius plot of for each calculated at selected temperatures for samples 1 (white squares) and 2 (black triangles).
Contour plot of the variance as a function of and for sample 3 at 908 K. The contour includes a confidence coefficient of . The confidence level indicates that with repeated experiments, of the cases will give and values with variances within this defined contour region. Contours up to represent a confidence level of 90%. Similarly, contours up to include 95%.
Local and global minima of the variance for values of at different . Contours are omitted for clarity. Calculations were done at 908 K (white markers) and 948 K (black markers) for samples 1 and 2 (triangles), 3 (circles), and 4 (squares). Global minima are encircled.
Description of samples used for this study.
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