Exploring the Potential of Si and Ge Amorphous Nanostructures for Photonic Applications

摘要

The design and synthesis of nanocomposite thin films based on Si or Ge amorphous nanostructures embedded in amorphous aluminum oxide (a-Al_2O_3) is investigated in order to achieve a tunable optical response. Multilayered films have been prepared by alternated pulsed laser deposition of semiconductor and host materials at room temperature without post-deposition annealing. The optical response of the obtained films shows evidence of quantum confinement effects in the semiconductor nanostructures, the effective optical band-gap ranging from 2 eV to 3 eV for a-Si and from 1 eV to 4 eV for a-Ge. The sensitizing capabilities of Si nanostructures for enhancing the 1.53 μm Er~(3+) photoluminescence are demonstrated in a single nanostructured a-Si/Er layer. Finally, strategies for the optimized design of a simple photonic thin film structure based on a single optically active layer are discussed.