H. Teisseyre et al., The influence of erbium on the physical properties of GaN crystals grown from N solution in Ga at high nitrogen pressure, HIGH PR RES, 18(1-6), 2000, pp. 35-39
Oxygen contamination is the main source of free electrons in bulk GaN grown
at high-pressure. We used erbium as a promising getter/compensation center
to reduce the electron content in GaN. Both optical and electrical measure
ments indicate the reduction of electron concentration from the initial 6 x
10(19) cm(-3) down to 1 x 10(19) cm(-3) A photoluminescence study proves t
hat erbium is incorporated into the GaN host lattice, and emits light at si
milar to 1.5 mum.