Photoluminescence Properties Of Si Research Articles

Luminescence Efficiency of Si/SiO2 Nanoparticles Produced by Laser Ablation

Photoluminescence properties of Si(core)/SiO2(shell) nanoparticles produced by pulsed laser ablation in aqueous solution are investigated with the purpose to highlight the microscopic processes that govern the emission brightness and stability. Time resolved spectra evidence that these systems emit a µs decaying band centered around 1.95 eV, that is associated with the radiative recombination of quantum‐confined excitons generated in the Si nanocrystalline core. Both the quantum efficiency and the stability of this emission are strongly dependent on the pH level of the solution, that is changed after the laser ablation is performed. They enhance in acid environment because of the H+ passivation of non radiative defects, located in the Si/SiO2 interface, which causes the growth of IR‐active SiH groups. On the basis of the reported experimental results and previous literature data, we propose that the non radiative defects are located in the suboxide interlayer between Si and SiO2 and their nature is affected by the latter.

Optical properties of Si–N doped BaMgAl 10O 17:Eu 2+, Mn 2+ phosphors for plasma display panels

The photoluminescence properties of Si–N doped BaMgAl 10O 17:Eu 2+, Mn 2+ phosphors were studied. Photoluminescence spectrum, powder X-ray diffraction and decay curves were used. The electronic structure of un-doped BaMgAl 10O 17 was investigated by using the density functional theory. It reveals that an ideal hexagonal shape and particle size in 3–5 μm are obtained by Si–N doping. Additionally, its photoluminescence and thermal stability are both improved. The energy transfer from Eu 2+ to Mn 2+ also enhanced by suitable Si–N doping. These are expected to be potentially applicable to industrial production of the phosphor in plasma display panels.

High Volume Synthesis of Silicon Nanopowder by Electron Beam Ablation of Silicon Ingot at Atmospheric Pressure

The evaporation of high purity silicon ingot was performed in Ar, N2, and air atmospheres using a power electron accelerator. The obtained powders with primary particle sizes of 10–500 nm were investigated using Brunauer–Emmett–Teller analysis (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence measurement, and Raman spectroscopy. The structure and photoluminescence properties of Si(Ar) nanopowder obtained at a large quenching rate differ substantially from those of Si(Ar) and Si(N2) obtained at a smaller quenching rate. Photoluminescence peaks in the visible region of the spectrum are detected at room temperature for the Si(Ar) nanopowders.

Time-Integrated and Time-Resolved Photoluminescence Properties of Si Nanocrystal/SiO2 Multilayers Grown by Ion-Beam Sputtering

Time-Integrated and Time-Resolved Photoluminescence Properties of Si Nanocrystal/SiO2 Multilayers Grown by Ion-Beam Sputtering

Structural relaxation and its effects on photoluminescence properties in Si quantum wires

We calculate structural relaxation for a Si quantum wire in order to determine the mechanism of the efficient photoluminescence (PL) from Si. We find that structural relaxation, which has been ignored in most previous works, has a strong correlation to the PL properties of Si. The total energy of the quantum wire is optimized within the framework of the tight-binding (TB) approximation. The resultant structures for the ground and excited states have different band gaps, which accounts for the luminescence Stokes shift observed in experiments. We also find that the relaxation greatly improves the oscillator strength for the transition between band edges, which gives a great improvement in the luminescence efficiency.