Erbium-doped hydrogenated amorphous silicon prepared by dc sputtering

Highly erbium-doped hydrogenated amorphous silicon (a-Si : H(Er)) thin film s were deposited by de magnetron sputtering. Erbium was incorporated into t he host material by a co-sputtering technique. Deposited films (0.5-1.1 mu m thick) were characterized by optical transmission, Rutherford back-scatte ring spectrometry (RBS), secondary-ion mass spectrometry (SIMS) and electri cal measurements. RES and SIMS measurements clearly showed evidence for erb ium incorporation, with a concentration at about 1-2%, throughout the whole film thickness. This erbium incorporation induced an increase in the refra ctive-index value (from 3.2 to 3.55) and a decrease in the optical gap ener gy value to 1.14eV. Moreover, we observed a strong decrease in the electric al resistivity (from 10(8) to 5500 Omega cm) in a-Si : H(Er) films compared with undoped a-Si:H films. These results offer new possibilities for appli cation to optoelectronic devices (waveguides, light emitting diodes, etc.).