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1.
SnO 2 thin films undoped and doped with antimony (Sb), erbium (Er) and Si nanocrystals (Si-nc) have been grown on silicon (Si) substrate using sol-gel method. Room-temperature photoluminescence (PL) measurement of undoped SnO 2, under excitation at 280 nm, shows only one broad emission at 395 nm, which is related to oxygen vacancies. The PL of Er 3+ ions was found to be enhanced after doping SnO 2 with Sb and Si-nc. The excitation process of Er is studied and discussed. The calculation of cross-section suggests a sensitisation of Er PL by Si-nc. 相似文献
2.
The Antimony-doped tin oxide (SnO 2:Sb) films have been prepared on glass substrates by RF magnetron sputtering method. The prepared samples are polycrystalline films with rutile structure of pure SnO 2 and have preferred orientation of (1 1 0) direction. XRD measurement did not detect the existence of Sb 2O 3 phase and Sb 2O 5 phase; Sb ions occupy the site of Sn ions and form the substitution doping. An intensive UV-violet luminescence peak near 392 nm is observed at room temperature. Photoluminescence (PL) properties influenced by sputtering power and annealing for the SnO 2:Sb films are investigated in detail and corresponding PL mechanism is discussed. 相似文献
3.
SnO 2-CuO nanocomposite was synthesized by impregnating SnO 2 nanowires with CuCl 2 solution and subsequent calcination. SEM and XRD were used to characterize the morphology and structure of the product. The optical properties were analyzed by Raman and photoluminescence (PL) spectra at room temperature. Except the strong orange emission of SnO 2, the PL spectrum showed a red shoulder at 678 nm which originated from the interface between SnO 2 and CuO. 相似文献
4.
SnO 2 thin films have been successfully deposited on α-Al 2O 3 (0 1 2) substrates by metalorganic chemical vapor deposition (MOCVD) in the temperature range 500-700 °C. The films were epitaxially grown in the tetragonal SnO 2 phase and were (1 0 1) oriented. In-plane orientation relationship [0 1 0]SnO 2||[1 0 0]Al 2O 3 and [1 0 1?]SnO 2||[1? 2? 1]Al 2O 3 was determined between the film and substrate. Photoluminescence (PL) spectra measured at room temperature revealed that the film grown at 700 °C showed an intense ultra-violet (UV) PL peak at 333 nm, which was a band-edge emission peak in SnO 2 films. At a temperature of 13 K, a new broad PL band centered at about 480 nm was observed. The corresponding PL mechanisms are discussed in detail. 相似文献
5.
Tin oxide (SnO 2)-layers-doped terbium and europium ions are elaborated by the sol-gel method on silicon substrates. After annealing at 500 °C, the transmission electron microscopy revealed a crystallization of tin oxide.The emission properties of rare-earth in SnO 2 are studied systematically against temperature annealing and Tb 3+ concentration. The PL spectrum is optimal after annealing at 900 °C and the corresponding photoluminescence (PL) decay is nearly exponential, showing that the sample is homogenous and the PL process can be described by two levels system.The concentration effect shows a quenching of the PL intensity for Tb 3+ concentration above 4%. From the investigation of the decay rate from the 7F 5 state within terbium concentration, we show that self-quenching is insured by dipole - dipole interaction. The evolutions of both PL intensity and PL lifetime versus temperature are studied. The PL intensity and PL lifetime are enhanced by deposing SnO 2:Tb 3+ and SnO 2:Eu 3+ in porous silicon. We show that an efficient excitation transfer from Si nanocrystallites to RE ions can occur. 相似文献
6.
用射频磁控溅射法在蓝宝石(0001)衬底上制备出锑掺杂的氧化锡(SnO 2:Sb)薄膜.对制备薄膜的结构和发光性质进行了研究.制备样品为多晶薄膜,具有纯SnO 2的四方金红石结构.室温条件下对样品进行光致发光测量,在334 nm附近观测到紫外发射峰,并对SnO 2:Sb的光致发光机制进行了研究. 相似文献
7.
The present investigation has been carried out to optimize the pH level of lanthanum (La)-doped tin dioxide (SnO2) nanoparticles towards the potential application in gas sensor. The La-doped SnO2 nanoparticles were synthesized by sol-gel method in different pH values varying from acidic to base nature. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), ultraviolet (UV), photoluminescence (PL), and scanning electron microscopy (SEM) techniques. The XRD, UV, and PL analyses show the pH influences on the crystallite size of La-doped SnO2 nanoparticles. The SEM images show the formation of porous structure at pH 11. Also, the electrical conductivity of 1 mol% La-doped SnO2 at pH 3 and pH 11 were measured by impedance analyzer. In addition, we have fabricated and demonstrated device performance of synthesized La-doped SnO2 nanoparticles for gas-sensing application. Real-time current response and long-time response to the gas sensing were also studied for the fabricated device. 相似文献
8.
We have investigated the optical properties of sol-gel thin films of tin dioxide (SnO 2) codoped with Er 3+-Yb 3+ as a function of Yb 3+ concentration. The Judd-Ofelt model has been applied to absorption intensities of Er 3+ (4f 11) transitions to establish the so-called Judd-Ofelt intensity parameters: Ω2, Ω4, Ω6. Various spectroscopic parameters were obtained to evaluate their dependence and the potential of the samples as a laser material in the eye-safe laser wavelength (1.53 μm) as a function of Yb 3+ concentration. An amelioration of the quality factor Ω4/ Ω6 was found with Yb content. Both the IR photoluminescence (PL) intensity and the up-conversion emission, from Er 3+ ion in SnO 2, were found to increase with Yb concentration. We show that the Yb 3+ ion acts as sensitizer for Er 3+ ion and contributes largely to the improvement of the spectroscopic properties of SnO 2:Er. The mechanism of up-conversion emission is discussed and a model is proposed. The results showed that sol-gel SnO 2 is promising gain media for developing the solid-state 1.5 μm optical amplifiers and tunable up-conversion lasers. 相似文献
9.
We reported an approach, in which we have produced the nano-sized crystalline tin oxide (SnO 2) particles with rutile structure. SnO 2 nanowires were coated with a shell layer of SiO x via a sputtering method. Transmission electron microscopy and elemental mapping investigations revealed that the nanostructures consisted of a crystalline SnO 2 core surrounded by an amorphous SiO x sheath. The annealing effects on the core-shell nanowires were investigated, revealing that the outer surface became rougher by the thermal annealing. For core-shell nanowires, a room-temperature PL measurement with a Gaussian fitting showed yellow, blue, and violet light emission bands, with the relative intensity of the yellow band showing an increase after thermal annealing. Possible PL emission mechanisms are discussed. This study reveals that the sputtering is effective for preparing the shell layers of nanocables. 相似文献
10.
The pump fluence dependent photoluminescence (PL) spectra of SnO 2 nanowires were investigated, which were synthesized with a high-temperature chemical reduction method. The integrated intensity of the narrower peak at 3.2 eV experiences a strong superlinear dependence on the pump fluence, and the narrowest width of the sharp peak is only 19 meV. Moreover, under high excitation fluence, an ultrafast decay time (less than 20 ps) appears in the time-resolved PL spectra. The emission of these SnO 2 nanowires shows strong apparent stimulated emission behaviors although the SnO 2 is a dipole forbidden direct gap semiconductor. The stimulated emission should relate to the localized islands on the surface of nanowire, which was observed through the high resolution transmission electron microscopy (HRTEM) image. The giant-oscillator-strength effect of bound exciton generated from the localized islands was considered to induce the stimulated emission of SnO 2 nanowires. 相似文献
11.
Aligned tin dioxide (SnO 2) nanotubes have been synthesized by high-frequency inductive heating. Nanotubes with high yield were grown on silicon substrates in less than 5 min, using SnO 2 and graphite as the source powder. Scanning electron microscopy and transmission electron microscopy showed nanotube with diameters from 50 to 100 nm and lengths up to tens of mircrometers. The SnO 2 nanotubes synthesized under the optimum condition have better field-emission characteristics. The turn-on field needed to produce a current density of 10 μA/cm 2 is found to be 1.64 V/μm. The samples show good field-emission properties with a fairly stable emission current. This type of SnO 2 nanotubes can be applied as field emitters in displays as well as vacuum electric devices. 相似文献
12.
We present a strategy to synthesize porous BaSnO 3 hollow architectures with that were 150-300 nm in diameter and 1.5-5 μm in length using precursor of BaCO 3@SnO 2 nanorods prepared by hydrothermal treatment. BaCO 3@SnO 2 nanorods, consisting of a BaCO 3 core and a SnO 2 shell, could be used effectively for the solid-state synthesis of polycrystalline BaSnO 3 powder at 800 °C (lower than convention for BaCO 3 and SnO 2 mixtures). The core/shell structure of the precursor could play a role as a structural directing template for preparing BaSnO 3 hollow architectures during the calcination process. The X-ray diffractometer (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) are employed to characterize the structures and morphologies. When applied to DSSC, the porous BaSnO 3 hollow architectures exhibit distinct photovoltaic effect. 相似文献
13.
CuO-core/ SnO 2-shell one-dimensional nanostructures have been fabricated by thermal oxidation of a copper foil and then atomic layer deposition of SnO 2. The structure and optical properties of the nanostructures have been investigated by using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, photoluminescence (PL) spectroscopy, and energy-dispersive X-ray analysis techniques. The nanostructures are found to have the form of nanorods, with the diameter of the CuO cores being in the range from a few tens to a few hundreds of nanometers, the thickness of the SnO 2 shells being ~15 nm, and with a length of a few tens of micrometers. The CuO cores and the SnO 2 shells of the as-synthesized nanorods have crystalline monoclinic CuO and amorphous SnO 2 structures, respectively, but the SnO 2 shells are found to crystallize to tetragonal SnO 2 on thermal annealing. The PL emission intensity of the CuO nanorods has been slightly increased by SnO 2 coating. The PL emission of the SnO 2-coated CuO nanorods is somewhat increased and the emission peak position is red-shifted from 550 to 580 nm by annealing in a reducing atmosphere. On the other hand, the PL emission is significantly increased and the emission peak position is shifted from 550 nm further to around 595 nm by annealing in an oxidative atmosphere. In addition, the origins of the PL enhancements in the nanorods by coating and annealing are discussed. 相似文献
14.
Porous tin oxide was prepared on silicon(111) substrate by the sol–gel route. Then, the samples were dried in air at 600°C for 30 min in an electric furnace. Scanning electron microscope (SEM) images indicated the high density of the pores. Circular microvoids formed by the rigid shaped microarray network of 200–300 nm sizes are clearly seen in the plan view SEM image. The high homogeneity and uniformity of the porous region could also be visualized by this easy method. Nanocrystalline zinc oxide (ZnO) thin films have been deposited onto porous SnO 2substrates at high growth rates by radio frequency (RF) sputtering using a ZnO target. The surface morphology of the nanocrystalline ZnO films was characterized by scanning electron microscope (SEM). Photoluminescence (PL) spectroscopy is a powerful, contactless and excellent nondestructive optical tool to study the acceptor binding energy of ZnO nanostructures. The PL measurements were also operated at room temperature. The peak luminescence energy in nanocrystalline ZnO on porous SnO 2 is blue-shifted with regard to that in bulk ZnO (381 nm). PL spectra peaks are distinctly apparent at 375 nm for ZnO film grown on porous SnO 2/Si(111) substrates. 相似文献
15.
Zn 2SnO 4:Eu 3+ nanocrystals were one-step synthesized by hydrothermal method for the first time. All the products were systematically characterized by powder X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), electron probe X-ray microanalyzer (EPMA), photoluminescence (PL) and photoluminescent excitation (PLE). The characteristic peak of Eu 3+-doped in Zn 2SnO 4 nanocrystals was also detected. The luminescent properties of blank and Eu 3+-doped Zn 2SnO 4 nanocrystals were reported. 相似文献
16.
SnO 2:Eu and SnO 2:Eu nanoparticles dispersed in silica matrix were prepared at a relatively low temperature of 185 °C in ethylene glycol medium. For as-prepared SnO 2:Eu nanoparticles there exists a weak energy transfer from the SnO 2 host to the Eu 3+ ions. However, the energy transfer can be significantly improved by dispersing the Eu 3+-doped SnO 2 nanoparticles in silica matrix. Effective shielding of surface Eu 3+ ions in SnO 2:Eu nanoparticles from the stabilizing ligand by silica matrix is the reason for the improved extent of energy transfer. Increase in asymmetric ratio of luminescence (ratio of the intensity of the electric dipole allowed transition, 5D 0→ 7F 2, to magnetic dipole allowed transition, 5D 0→ 7F 1) for SnO 2:Eu nanoparticles dispersed in silica compared to that of SnO 2:Eu nanoparticles, has been attributed to the distorted environment around surface Eu 3+ ions brought about by the presence of both tin and silicon structural units. 119Sn and 29Si MAS NMR studies on this sample confirmed that there is no interaction between the tin and silicon structural units even after heating the samples at 900 °C. 相似文献
17.
This work presents the influence of europium dopant on optical properties of Sr 2SnO 4:Eu 3+ powders fabricated by a facile low temperature method. Powders were obtained from the same amounts of Eu 3+ doping into the different concentrations of Sr(NO 3) 2. Powders were examined by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL). SEM measurements different Eu concentrations in fabricated powders was determined to found different morphologies. XRD analysis revealed the existence of crystalline Sr 2SnO 4 in the form of tetragonal and the diffraction intensity was remarkably changed. PL studies showed a red luminescence of Sr 2SnO 4:Eu 3+ powders. The intensity of luminescence increased with better crystallinity. This approach provides economically viable route for large-scale synthesis of this kind of nanopowders. 相似文献
18.
In recent times, considerable research efforts have been focused on the exploration of novel optical properties of nanocrystalline
SnO 2 particles such as photoluminescence (PL). In the present work, spherical SnO 2 nanoparticles are synthesized by solid state reaction at different temperatures using tin chloride dihydrate and sodium hydroxide
flakes as precursors. Transmission electron micrograph shows uniform and spherical SnO 2 nanoparticles of diameter 30–40 nm. Micro-Raman spectra show an inverse relationship of line-width with SnO 2 particle size. The band gap of SnO 2 is calculated by plotting ( αhν) 2
vs. hν and extrapolating the linear portion of it to α = 0 and found it to be 3.76–4.24 eV. Photoluminescence intensity increases with the increase of solid state reaction temperature
up to 873 K. This is attributed to the generation of the oxygen ion vacancies in SnO 2. 相似文献
19.
We investigated the influence of the ZnO coating on the properties of one-dimensional (1D) nanostructures of SnO 2. We have employed X-ray diffraction, scanning electron microscope, transmission electron microscope and photoluminescence (PL) spectroscopy to characterize both as-synthesized and ZnO-coated products. We observed that deposition process of ZnO by using an atomic layer deposition technique resulted in the SnO 2 core/ZnO shell structure. The photoluminescence of the ZnO-coated products exhibited broad bands in the UV and green region, suggesting a possible contribution of the emission from the ZnO outlayers. 相似文献
20.
The possibilities of magnetism induced by intrinsic defects and nitrogen substitution in (5,5) single-wall SnO 2 nanotube are investigated by ab initio calculations. The calculated results indicate that a stoichiometric SnO 2 nanotube is nonmagnetic. The tin (Sn) vacancy can induce the magnetic moments rather than oxygen vacancy, which is originated from the polarization of O 2 p electrons. A couple of tin vacancies can lead to the ferromagnetic coupling. A nitrogen substitution for oxygen also produces magnetic moments. When substituting two nitrogen atoms, the characteristics of exchange coupling depend upon the distance of two nitrogen atoms. The longer distance of two nitrogen atoms prefers the ferromagnetic coupling, whereas the short distance leads to the antiferromagnetic coupling. 相似文献
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