Persistent photocurrent effects in GaN/AlGaN multiquantum wells

PhotoCurrent (PC) experiments on GaN/AlGaN multiple quantum wells, both spectrally and temporally resolved, have shown that a photopersistence effect exists in our samples even at room temperature. A peak in the rise and decay times of PC vs. time appears in correspondence of wavelengths typical of Yellow-Band features while this is not seen in PL. This fact seems to indicate that YB defects give rise here to carrier trapping rather than recombination. Furthermore, the observed persistence times seem to be peculiar of MultiQuantum Wells and this possibly calls into play the role of built-in fields in the defects dynamics