Room-temperature silicon band-edge photoluminescence enhanced by spin-coated sol–gel films

Photoluminescence is observed at room temperature from phonon-assisted band-to-band emission in Si (1.067 eV peak) using unpatterned bulk p-type silicon wafer samples that were spin-coated with Er-doped (6 at.%) silica-gel films (0.13 μm) and vacuum annealed; the strongest emission was obtained at ∼700 °C. Comparative study of annealing behavior indicates an efficiency enhancement of two orders of magnitude. Emission from Er3+ ions in the silica film is used to gauge relative emission strengths. Mechanisms for inducing emission from silicon utilizing stresses in sol–gel films are discussed.