Carrier relaxation dynamics for As defects in GaN

Long decay times in the 50–150 ns range have been measured for the characteristic blue photoluminescence that peaks at 2.6 eV in GaN:As. We interpret these long decay times according to the theoretical predictions that this blue photoluminescence is caused by the incorporation of arsenic on the gallium site. The long decay times are characteristics of the large lattice relaxation for such a deep donor with a negative-U center behavior.