A comparative study on GaN luminescence under/after inductively coupled plasma exposure

GaN luminescence, induced by ultraviolet light under/after inductively coupled plasma exposure, has been measured in situ and ex situ. After the plasma exposure, both near-band edge (NBE) and yellow luminescence (YL) intensities decrease. The decay times of NBE and YL in the in situ measurement are shorter than those of the ex situ measurement on account of the temperature rise induced by the plasma. On the other hand, with increasing plasma power, the decay times decrease. It is considered that this decrease is strongly related to non-radiative defects introduced by the Ar plasma. The results suggest that in situ photoluminescence monitoring can be used to reveal plasma-induced damage at GaN surfaces.