Erbium emission from nanoengineered silicon surface (original) (raw)
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Optical emission from erbium-doped silica nanowires
2008
Abstract Infrared optical emission from erbium-doped silica nanowires is shown to have property characteristic of the material nanostructure and to provide the basis for the fabrication of integrated photonic devices and biosensors. Silica nanowires of approximately 150 nm diameter were grown on a silicon wafer by metal-induced growth using a thin (20 nm) sputter-deposited palladium layer as a catalyst.
Physical Review B, 2004
We report a soft x-ray excited optical luminescence (XEOL) and x-ray emission spectroscopy (XES) study of silicon nanowires (SiNW) with excitations at the silicon K and L 3,2 edge, respectively. It is found that the XEOL of SiNW exhibits several luminescence bands at 460, 530, and 630 nm. These luminescence bands are broad and are sensitive to the Si 1s excitation channel (Si versus SiO 2 whiteline). These chemical-and morphology-dependent luminescences are attributable to the emission from the encapsulating silicon oxide, the quantum-confined silicon crystallites of various sizes embedded in the oxide layer, and the silicon-silicon oxide interface. XES clearly shows the presence of a relatively thick oxide layer encapsulating the silicon nanowire and the densities of states tailing across the Fermi level. The implications of these findings to the electronic and optical properties of silicon nanowires are discussed.
Photoluminescence of erbium ions in heterostructures with silicon nanocrystals
Semiconductors, 2006
Photoluminescence properties of erbium-doped silicon dioxide layers containing silicon nanocrystals with 1.5-4.5 nm average size are investigated. It is found that the intensity and mean lifetime of the Er 3+-ion photoluminescence depend on the nanocrystal size, optical pump intensity, and temperature. The results obtained are explained both by the effect of the local environment on Er 3+ ions and by the manifestation of nonradiative deexcitation of ions caused by the transfer of energy back into the solid-state matrix and the Auger processes.
Physics of the Solid State, 2005
The photoluminescence (PL) spectra and kinetics of erbium-doped layers of silicon nanocrystals dispersed in a silicon dioxide matrix (nc-Si/SiO 2) are studied. It was found that optical excitation of nc-Si can be transferred with a high efficiency to Er 3+ ions present in the surrounding oxide. The efficiency of energy transfer increases with increasing pumping photon energy and intensity. The process of Er 3+ excitation is shown to compete successfully with nonradiative recombination in the nc-Si/SiO 2 structures. The Er 3+ PL lifetime was found to decrease under intense optical pumping, which implies the establishment of inverse population in the Er 3+ system. The results obtained demonstrate the very high potential of erbium-doped nc-Si/SiO 2 structures when used as active media for optical amplifiers and light-emitting devices operating at a wavelength of 1.5 µ m.
Erbium environment in silicon nanoparticles
Journal of Non-crystalline Solids, 2002
The Er environment in two sets of Er-doped Si nanoparticles (np) with nominal Er concentrations of 1-2 at.% was measured by EXAFS. Set H, with a homogeneous distribution of Er atoms, consist of samples with average np diameters of 3.2, 5.9, and 6.4 nm. The np of set C consist of a Si core covered by an Er-rich shell, with average diameters of 26 and 22 nm, nearly an order of magnitude higher than those of set H. The Er atoms in the np are coordinated to oxygen, like in the ErðtmhdÞ 3 organometallic precursor. In set H, both the Er coordination and the average Er-O separation increase as the average nanoparticle diameter increases from 3.2 to 6.4 nm. The results for small np are remarkably similar to those found for Er in a-Si:HhEri, indicating that the lattice constraints in the np are very similar to a-Si:H. Efficient Er 3þ luminescence is detected in as-prepared samples. As the particle size increases the Er environment becomes Er 2 O 3 -like, as in bulk Czochralski silicon. In set C, the Er environment in both samples is similar to that in ErðtmhdÞ 3 and in Er 2 O 3 , but the Er-O distances are larger. Ó
Ion Implantation Based Selective Synthesis of Silica Nanowires on Silicon Wafers
Applied Physics Letters, 2006
A new method for selective growth of silica nanowires on silicon wafers is demonstrated by using ion implantation through a mask. Pd ions are implanted into Si ͑100͒ to form nanoclusters of Pd. The nanoclusters get activated and act as catalyst silicide seeds for nanowire growth, when heated in an open tube quartz furnace, using Ar as carrier gas. Silica nanowires grow selectively only on the implanted region. The vapor-liquid-solid model of nanowire formation is shown to be valid. This method facilitates controlled localized and directed bottom-up growth of silica nanowires and may enable applications such as in on-chip optoelectronics, biosensors, microantennae, and metallic nanotubes.
Synthesis and optical properties of silicon nanowires grown by different methods
2006
Abstract We review our recent results on the growth and characterization of silicon nanowires (SiNWs). Vapour-phase deposition techniques are considered, including chemical vapour deposition (CVD), plasma-enhanced chemical vapour deposition (PECVD), high-temperature annealing, and thermal evaporation. We present complementary approaches to SiNW production. We investigate the low-temperature (down to 300 C) selective nucleation of SiNWs by Au-catalysed CVD and PECVD.
Synthesis of Silicon Nanocrystals with Erbium-Rich Surface Layers
Nano Letters, 2001
A route to silicon nanocrystals with erbium-rich surface layers is described involving the initial pyrolysis of disilane to produce nucleation and growth of the Si core followed by a second thermal annealing step in the presence of the volatile complex Er(tmhd) 3 (tmhd ) 2,2,6,6tetramethyl-3,5-heptanedionato). These nanoparticles were structurally characterized by transmission electron microscopy, selected area electron diffraction, energy-dispersive X-ray analysis, and extended X-ray absorption fine structure methods, while spectroscopic characterization was achieved via photoluminescence and UV−visible absorption spectroscopies. The effects of altering the length of the pyrolysis oven and its temperature, the disilane flow rate, and the Er(tmhd) 3 /helium carrier gas flow rate on the mean nanoparticle feature size are noted. Interestingly, the characteristic Er 3+ near-infrared photoluminescence at 1540 nm is not detected in the as-formed nanoparticles but can be observed after a brief vacuum anneal at 800°C.