Phosphorous-doped hydrogenated amorphous Si/SiO multilayer structures are fabricated in a plasma enhanced chemical vapor deposition system.The microstructural and luminescence properties of the samples are charac- terized after annealing at various temperatures.Under the onset crystallization temperature 800-900℃, a strong subband infrared light emission in the range 1.1-1.8μm is observed at room temperature instead of the usually observed visible light emission.This subband infrared emission is gradually enhanced with the increase of phos- phorus doping concentration, which can be ascribed to the increase of the luminescent defect states promoted by the doped phosphorous atoms.