This work presents additional physical results about the enhancement of the photoluminescence property of hybrid structures using single walled carbon nanotubes/pyramidal porous silicon surface, in comparison with what has already been published on these structures in terms of synthesis conditions and FTIR investigations as reported recently by the same authors in Journal of Alloys and Compounds 694 (2017) 1036 1044. Herein, the effect of the single walled carbon nanotubes (SWCNTs) layer on the optical properties of pyramidal Porous Silicon (pPSi) in hybrid SWCNTs/pPSi structure synthetized by chemical and electrochemical etching of silicon wafer was studied. Using both scanning electron mi croscopy (SEM), SWCNTs formed a thin film on pPSi surface and they are partly embedded in its pores. An analysis of Raman spectra for the realized structures confirmed the passivation of pPSi surface by SWCNTs film. The surface bond configurations were also monitored. Moreover, SWCNTs modified Pho toluminescence (PL) spectrum of pPSi by shifting PL peaks towards high energies, showed that the defect created in the materials can result in an efficient and stabilized photoluminescence response on Silicon (Si).
In this work, we study the inclusion mechanism of Fe 3? ions in a polyvinyl alcohol (PVA) matrix. Pure and Fe 3? -doped PVA films, using FeCl 3 solution, are prepared by a solution casting method. The effect of Fe 3? doping on the photoluminescence (PL) behavior of PVA is investigated in the temperature range from 10 to 300 K. The PL intensity is found to decrease as the temperature increases for the samples slightly doped. This behavior is attributed to the phonon diffusion by the photo-created electron-hole pairs. However, this behavior is completely inverted when the content of Fe 3? increases. The first author has already published a work discussing the possible explanations of such a behavior where the PL intensity increases with temperature. This paper is devoted to study the thermal activations energy and its variation with doping. Therefore, the PL integrated intensity as a function of 1/T is simulated by the Arrhenius model for the samples whose PL intensity decreases with temperature. However, for the other samples, a model of two activation energies is used. The gap energy values and the PL spectra of all samples at 300 K were used to justify the suggested transitions.
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