Luminescence characteristics of Ge nanocrystals embedded in SiO2 matrix

Germanium nanocrystals embedded in silicon dioxide matrix were grown using rf magnetron sputtering. The transmission electron micrograph showed the formation of nearly spherical nanocrystals evenly distributed in the oxide matrix. Annealed nanostructures exhibited strong and broad photoluminescence in the visible range at room temperature due to the quantum confinement of carriers in Ge nanocrystals. A trilayer structure consisting of the cap gate oxide, sputtered SiGe layers and thermally grown tunnel oxide was fabricated on p-Si substrates followed by rapid thermal annealing at 1000 °C in nitrogen atmosphere. The light emission from the trilayer structure manifests the quantum confinement of charge carriers in Ge nanocrystals, making it attractive for future nanocrystal memory devices.