Here, Er was diffused into GaN for the first time, and a weak spontaneous emission was found in the photoluminescence spectra after diffusion for 168h at 800C under N2. The diffusivity was found to be described by:

D (cm2/s) = 1.8 x 10-12 exp[-1(eV)/kT]

The results showed that the Er diffusion mechanism might be an interstitial-assisted process. The luminescence characteristics of Er-diffused GaN were compared with those of Er-implanted GaN.

Diffusion Mechanism and Photoluminescence of Erbium in GaN. Y.S.Ting, C.C.Chen, C.C.Lee, G.C.Chi, T.K.Chini, P.Chakraborty, H.W.Chuang, J.S.Tsang, C.T.Kuo, W.C.Tsai, S.H.Chen, J.I.Chyi: Optical Materials, 2003, 24[3], 515-8