Abstract: An n-type silicon (Si) wafer is galvanostatically etched in a hydrofluoric acid (HF)-containing solution while being illuminated with a 300 watt tungsten light source to form porous silicon with luminescent properties. Photoluminescence of the porous silicon is monitored using a short wavelength visible or ultraviolet light source and a monochromator/CCD detector assembly. Upon exposure to organic solvents, the photoluminescence is quenched. Within seconds of removal of the solvent, the original intensity is recovered and further exposure of the porous silicon to organic solvents will again result in quenching of the luminescence.

Abstract: A polished wafer of single-crystal silicon (Si) is ohmically contacted on its backside to a copper wire to provide a working electrode. The wafer and a counterelectrode are immersed in a solution of aqueous HF and ethanol within an optical quality cuvette. Lithographic images are projected onto the silicon wafer within the solution, and the wafer is etched galvanostatically at a low current density until a predetermined charge density is attained. The areas of an n-type silicon wafer exposed to the light during the etch will exhibit visible luminescence when the wafer is illuminated with an ultraviolet (UV) lamp or other short wavelength visible light. The areas of the wafer that were not exposed to the pattern during etch will not luminesce.