DIRECT AND INDIRECT EXCITATION OF ER3-ALN( IONS IN ER)

Photoluminescence (PL) excitation and time-resolved PL measurements we re conducted on erbium doped AlN. The Er:AlN film was grown by metal o rganic molecular beam epitaxy with a solid Er effusion source. The res ulting Er concentration was 2-5X10(19) Er/cm(3). Photoluminescence exc itation measurements revealed that Er3+ in Er:AlN can be excited eithe r through direct optical pumping into Er3+ 4f levels or through an ind irect carrier-mediated process. With respect to these two Er3+ excitat ion schemes, distinct Er3+ PL decay patterns were observed. The Er3+ P L excited by direct optical excitation was longer lived than that exci ted via a carrier-mediated process, Time-resolved PL measurements supp ort that at least two classes of Er3+ PL centers exist in Er:AlN, and that direct optical excitation of Er3+ 4f levels primarily excites a s et of longer-lived Er3+ sites which are not excited through carrier-me diated processes. (C) 1997 American Institute of Physics.