Evolution of photoluminescence life-times distribution in Si-QD/SiO2 multilayer films
College of Physics Science and Technology, Hebei University, Baoding
071002, P.R. China
Revised: 8 May 2013
Accepted: 14 May 2013
Published online: 11 June 2013
Si-rich oxide/SiO2 multilayer films with different N2O flow rates have been deposited by plasma enhanced chemical vapor deposition technique, and Si quantum dot (Si-QD)/SiO2 multilayer films are obtained by 1100 °C annealing. Steady photoluminescence (PL) spectra show that the main optical emission mechanism changes from quantum confinement effect of Si-QDs to interface defect states with increasing the flow rate of N2O. Curve fittings of time-resolved PL spectra show that two log-normal decay time distribution bands are obtained, and both the most frequent life-times decrease with increasing the flow rate of N2O, while increase with the red shift of detecting wavelength. Analyses indicate that defect states density and size distribution of Si-QDs strongly influence the PL decay properties.
© EDP Sciences, 2013