Example of streak camera image

Isointensity plot of spectrally and temporally resolved photoluminescence of a GaN/AlGaN sample measured with a streak-camera:

The image is presented in logarithmic scale in order to show weak peaks of phonon replicas.

Some physical observations:

Lines in the AlGaN layer have higher energy due to wider band-gap than in GaN. Moreover lines in AlGaN are broader than in the GaN layer, due to Al/Ga alloy fluctuations.
It is interesting to notice that free excitons (FX) have much shorter lifetimes and broader lines than donor-bound excitons (DX). The FX are also much weaker than DX, so in order to analyze properly the FX transients, it is necessary to measure simultaneously DX and FX luminescence and than subtract DX-related background from the FX transient.
Another interesting point is that phonon replicas of the FX lines are stronger than phonon replicas of the DX lines. It is because FX recombination by emission of single photon breaks momentum conservation rule. On the other hand, FX recombination with simultaneous emission of photon and phonon conserves both energy and momentum.