Spectroscopic properties of Sm3+(4f5) in GaN

We have analyzed the cathodoluminescence spectra of Sm3+ ions implanted and annealed in GaN epilayers. High-resolution emission spectra were obtained at 11 K between 350 and 1050 nm, representing transitions from the (4)G(5/2) to the H-6(J) and F-6(J) manifolds of Sm3+(4f(5)). Emission lifetimes were determined at various temperatures between 7 and 320 K for transitions from (4)G(5/2) to H-6(5/2), H-6(7/2), and H-6(9/2). Lattice-sum calculations were carried out to determine the crystal-field splitting of the multiplet manifolds. With individual Stark levels and corresponding wave functions identified, the matrix elements for both electric-dipole and magnetic-dipole transitions were calculated between levels. Radiative lifetimes were calculated and compared with experimental lifetimes. High quantum efficiencies are reported. The calculated branching ratios for transitions from (4)G(5/2) to H-6(J) and F-6(J) manifolds indicate that transitions to H-6(5/2), H-6(7/2), and H-6(9/2) account for 80% of the total observed emission. (C) 2002 American Institute of Physics.