Site-selective luminescence studies of the 4I11/2 excited states of Er centers in 6H SiC

In this work the high-resolution site-selective photoluminescence (PL) using Fourier transform spectrometer and PL excitation spectra near 1.54 μm in Er-implanted 6H SiC were investigated. Evidence for the existence of three different Er3+ centers emitting near 1.54 μm has been confirmed. The Stark splitting of the 4I11/2 excited states for all three centers was determined. Site symmetry of the centers was analyzed using point charge model calculations for the 4I9/2 and 4I11/2 states. The centers reveal low-local symmetry, probably due to complexes with impurities and defects. It is shown, however, that symmetry of one of the centers is close to cubic.