Photoluminescence, photoluminescence excitation spectra and luminescence decay of the Er3+ 4I13/2 → 4I15/2 transition were investigated at 7K in Er-implanted samples. Under below-gap excitation, photoluminescence and photoluminescence excitation spectra revealed the existence of 2 types of Er center. One type of Er center which could only be excited by resonant intra 4f shell transition was predominant while other Er centers were clearly excited via local defects. Evolution of the Er luminescence as a function of implantation dose and implantation geometry was presented for both types of Er center. Luminescence dynamics studies showed that the 4I13/2 manifold had a shorter lifetime (about 1ms) when Er ions were part of Er-defect complexes than when Er ions were isolated from any defect (lifetime of 3.8ms). This result indicated the existence of non-radiative energy transfers in Er-defect complexes; from Er ions towards defects or impurities. The Er decay in Er-defect complexes was then successfully compared with classical energy transfer models.

Er-Defect Complexes and Isolated Er Center Spectroscopy in Er-Implanted GaN. A.Braud, J.L.Doualan, R.Moncorge, B.Pipeleers, A.Vantomme: Materials Science and Engineering B, 2003, 105[1-3], 100-4