  Nearly two-orders of magnitude increase in room-temperature band-to-band
(1.067 eV) infrared emission from crystalline silicon, coated with erbium-doped
sol-gel films, have been achieved. Phonon-assisted band-to-band emission from
coated and annealed p-Si is strongest for the sample annealed at
700$^{\circ}$C. In this paper, evidence of the origin of the emission band from
the band edge recombination activities is established. Enhancement of radiative
recombination of free carriers is reasoned by stresses at the interface due to
the annealed sol-gel deposited silica. Comparative studies with other strained
silicon samples are presented.
