On the nature of the stretched exponential photoluminescence decay for silicon nanocrystals

The influence of hydrogen rate on optical properties of silicon nanocrystals deposited by sputtering method was studied by means of time-resolved photoluminescence spectroscopy as well as transmission and reflection measurements. It was found that photoluminescence decay is strongly non-single exponential and can be described by the stretched exponential function. It was also shown that effective decay rate probability density function may be recovered by means of Stehfest algorithm. Moreover, it was proposed that the observed broadening of obtained decay rate distributions reflects the disorder in the samples

Size-Dependent Indirect Excitation of Trivalent Er Ions via Si Nanocrystals Embedded in a Silicon-Rich Silicon Oxide Matrix Deposited by ECR-PECVD

Silicon nanocrystals (Si-nc) embedded in a silicon-rich silicon oxide matrix codoped with Er3+ ions have been fabricated by electron-cyclotron plasma-enhanced chemical vapor deposition. Indirect excitation of erbium photoluminescence via silicon nanocrystals has been obtained within a broad pump wavelength range. The influence of different nanocrystal sizes on the excitation transfer from the Si-nc to Er3+ ions is discussed

On the nature of the stretched exponential photoluminescence decay for silicon nanocrystals

<p>Abstract</p> <p>The influence of hydrogen rate on optical properties of silicon nanocrystals deposited by sputtering method was studied by means of time-resolved photoluminescence spectroscopy as well as transmission and reflection measurements. It was found that photoluminescence decay is strongly non-single exponential and can be described by the stretched exponential function. It was also shown that effective decay rate probability density function may be recovered by means of Stehfest algorithm. Moreover, it was proposed that the observed broadening of obtained decay rate distributions reflects the disorder in the samples.</p

Influence of annealing temperature on the electron-lattice coupling strength in terbium doped yttrium alumina perovskite xerogels embedded in nano-porous anodic alumina

a b s t r a c t Terbium doped YAlO 3 xerogels were synthesized and spin-coated onto porous anodic alumina substrates. After deposition the films were annealed at temperatures between 400 and 1000°C. The influence of the annealing temperature on terbium emission and the terbium excitation mechanism were investigated by means of photoluminescence, photoluminescence decay and photoluminescence excitation spectroscopy. It was found that both photoluminescence lifetime and the energy difference between spin-forbidden and spin-allowed 4f-5d transitions decreases with the annealing temperature drop. This dependence was correlated to the electron-lattice coupling strength calculated as a function of annealing temperature

Temperature Dependent Emission Quenching for Silicon Nanoclusters

International audienceSilicon reach-silicon-oxide (SRSO) film containing silicon nanoclusters was obtained by the reactive magnetron sputtering. Photoluminescence (PL) spectra were measured as a function of temperature at different excitation wavelengths and additionally at different excitation power densities. Obtained PL spectra characterize by two emission bands centered at 1.6 and 2.4 eV. For these bands, temperature behaviour of PL intensities strongly differs but clearly correlate each other. Moreover, it has been observed that obtained PL intensities versus temperature exhibit a strong dependence on the excitation power density in the low temperature range

Correlation between matrix structural order and compressive stress exerted on silicon nanocrystals embedded in silicon-rich silicon oxide

International audienceSilicon nanocrystals embedded in a silicon oxide matrix were deposited by radio frequency reactive magnetron sputtering. By means of Raman spectroscopy, we have found that a compressive stress is exerted on the silicon nanocrystal cores. The stress varies as a function of silicon concentration in the silicon-rich silicon oxide layers varies, which can be attributed to changes of nanocrystal environment. By conducting the Fourier transform infrared absorption experiments, we have correlated the stresses exerted on the nanocrystal core to the degree of matrix structural order