Luminescence properties of Ammonium Silicon Fluoride films prepared by vapour etching technique

Photoluminescence (PL) properties of Ammonium Silicon Fluoride samples prepared by vapour etching technique are investigated with respect to excitation energy, excitation intensity and temperature. Ageing effect at ambient conditions is also examined by Fourier Transform Infrared Spectroscopy. PL peak maximum blue shifts as the excitation intensity increases and saturates at 2.106 eV. Temperature-dependent variations in PL peak energies and intensities cannot be thoroughly elucidated via Quantum Confinement model alone and require consideration of recombination rates at Si-SiO_x interface. Temperature dependence of integrated PL intensity is treated by a three-component functional form. Infrared absorption bands at 1060 cm^{- 1}, 1113 cm^{- 1} and 1230 cm^{- 1} attain saturation with time. Agreement between the saturation time of SiO_x longitudinal optic mode at 1230 cm^{- 1} and that deduced from PL measurements in literature is noted. It is shown that PL emissions are intrinsic in nature and have a significant excitonic contribution.