During the second half-cycle with NH3, high-intensity signals were observed for C2H6 compared to the TEG pulse, suggesting that more of these species were produced in the NH3 pulse than in the TEG pulse (Fig. ). Therefore, we suggest that ammonia molecules, or possibly NHx species in the plasma process , undergo a ligand exchange with surface-bound Ga centers to form a Ga-N bond and eliminate C2H6 as a byproduct. This is consistent with the QMS observations (Fig. ). Additionally, C2H5, which shows a signal during the NH3 pulse (Fig. ), possibly indicates the ongoing elimination of the ethyl groups due to the large amount of generated energetic species favoring ligand removal.