Preparation and characterization of ultrathin porous silicon films

Abstract

Light emitting porous silicon thin films with thicknesses from ∼0.1 to ∼100 μm were produced by electrochemical etching and subsequently lifted off the silicon wafer by an electropolishing step. The structural integrity of the thinner layers was maintained by deposition on sapphire windows where they remain attached by van der Waals or electrostatic forces. The procedure for manufacturing high quality layers and their structural and optical properties is discussed.