PHOTOLUMINESCENCE OF SOL-GEL-PREPARED ERBIUM-DOPED ALUMINA FILMS

Erbium-doped alumina films were prepared via sol-gel processing. The f ilms were produced by spinning onto single-crystal or polycrystalline silicon substrates, followed by heat treatment. The films were charact erized by scanning and transmission electron microscopy techniques, el lipsometry, and photoluminescence measurements at room temperature and 4.2 K. The films prepared on polycrystalline or unpolished silicon, w ith a rough surface relief, showed intracenter Er3+ luminescence aroun d 1.53 mu m at room temperature. This emission was also observed after heat treatment in air or vacuum at temperatures above 770 K. The 4.2- K photoluminescence spectra showed two peaks at 1.535 and 1.545 mu m. Erbium-doped alumina gel films are expected to be potential materials for silicon optoelectronics.