PHOTOLUMINESCENCE SPECTROSCOPY OF ERBIUM IMPLANTED GALLIUM NITRIDE

Results of a photoluminescence (PL) and photoluminescence excitation ( PLE) study of Er implanted GaN are presented. Upon optical excitation at 325 and 488 nm, we observed strong 1.54 mu m Er3+ PL which remained temperature stable from 15 to 550 K. At 550 K, the integrated PL inte nsity decreased by similar to 10% for above gap excitation (lambda(ex) = 325 nm) and similar to 50% for below gap excitation (lambda(ex) = 4 88 nm) relative to its value at 15 K. The excellent temperature stabil ity makes GaN:Er very attractive for high temperature optoelectronic d evice applications. PLE measurements were conducted to gain insight in to the Er3+ excitation mechanisms in the GaN host. The PLE results sho w that Er3+ be excited continuously over a broad wavelength region spa nning from 425 to 680 nm. In addition, sharp PLE features were observe d at approximately 495, 525, 553, 651, and 980 nm. The PLE spectrum su ggests that optically active Er3+ ions can be excited either through c arrier-mediated processes involving defects in the host or through res onant pumping into Er3+ 4f energy levels. With respect to these two ex citation schemes, distinct Er3+ PL properties were observed for resona nt and off-resonant Er3+ excitation indicating the presence of differe nt subsets of Er3+ ions in GaN. (C) 1997 American Institute of Physics .