首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到10条相似文献,搜索用时 62 毫秒
1.
Photoluminescence spectra of powdered ZnS thermally doped with MnS are studied. Correlations are demonstrated between variations in the luminescence characteristics of ZnS:Mn, on one hand, and some features of radiation center formation and the diffusion of Mn in ZnS after processing, on the other. It is found that after manganese doping at a temperature (T = 800°C) lower than the phase transition temperature of ZnS, relaxation processes owing to diffusion of Mn in ZnS take place in the material over times as long as 6.103 h. It is shown that 6.103 h after doping the α-MnS phase is essentially completely dissolved in the volume of the ZnS. Diffusion of Mn in powdered ZnS is found to occur via several channels, rapid diffusion along interior boundaries and slow diffusion via interstitial space, which indicates the existence of different activation energies for diffusion of Mn depending on its localization within the ZnS lattice.  相似文献   

2.
Formation of zinc sulfide nanocrystals in aqueous solutions of various polymers has been studied. Spectral properties of ZnS nanoparticles have been investigated, the structure of the long-wave edge of the fundamental absorption band of ZnS nanocrystals has been analyzed. It has been shown that the variation of the synthesis conditions (stabilizer nature and concentration, solution viscosity, ZnS concentration, etc.) allows tailoring of the ZnS nanocrystals size in the range of 3–10 nm. Photochemical processes in colloidal ZnS solutions, containing zinc chloride and sodium sulfite, have been investigated. It has been found that the irradiation of such solutions results in the reduction of Zn(II), the rate of this reaction growing at a decrease in the size of ZnS nanoparticles. Kinetics of photocatalytic Zn(II) reduction has been studied. It has been concluded that two-electron reduction of adsorbed Zn(II) species is the rate-determining stage of this reaction. Photocatalytic activity of ZnS nanoparticles in KAu(CN)2 reduction in aqueous solutions has been discovered. Spectral characteristics and kinetics of ZnS/Au0 nanocomposite formation have been studied. It has been shown that the photoreduction of gold(I) complex is the equilibrium reaction due to the reverse oxidation of gold nanoparticles by ZnS valence band holes.  相似文献   

3.
Chemical bath deposition of ZnS thin films from NH3/SC(NH2)2/ZnSO4 solutions has been studied. The effect of various process parameters on the growth and the film quality are presented. The influence on the growth rate of solution composition and the structural, optical properties of the ZnS thin films deposited by this method have been studied. The XRF analysis confirmed that volume of oxygen of the as-deposited film is very high. The XRD analysis of as-deposited films shows that the films are cubic ZnS structure. The XRD analysis of annealed films shows the annealed films are cubic ZnS and ZnO mixture structure. Those results confirmed that the as-deposited films have amorphous Zn(OH)2. SEM studies of the ZnS thin films grown on various growth phases show that ZnS film formed in the none-film phase is discontinuous. ZnS film formed in quasi-linear phase shows a compact and a granular structure with the grain size about 100 nm. There are adsorbed particles on films formed in the saturation phase. Transmission measurement shows that an optical transmittance is about 90% when the wavelength over 500 nm. The band gap (Eg) value of the deposited film is about 3.51 eV.  相似文献   

4.
Transient absorptions have been obtained in powdered samples of ZnS : Ag, ZnS : Cu and undoped ZnS at room temperature by the technique of diffuse reflectance laser flash photolysis. For the undoped material an absorption was detected that maximises at 400 nm and decays non-exponentially with an initial half-life of (6.8±1.0)×10?6s. The absorption is assigned to a transition within a donor impurity. In the cases of ZnS : Ag and ZnS : Cu, broad featureless absorptions in the 500–850 nm region were recorded. These decays are non-exponential and have initial half-lives of (3.1±0.2) ms and (0.48±0.05) ms for the Ag- and Cu-doped phosphors, respectively. These transient absorptions are considered to occur from electron traps introduced by the metal dopant. Laser-induced emission was also studied, and only in the case of undoped ZnS was a correlation observed between the decay of the weak emission at 520 nm and the decay of the transient absorption.  相似文献   

5.
Preparation of ZnS nanoparticles by ultrasonic radiation method   总被引:3,自引:0,他引:3  
2 S solution. ZnS nanoparticles were synthesized under ultrasonic radiation. They were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV spectrophotometry, and X-rayphotoelectron spectrometry (XPS). XRD revealed that the ZnS nanoparticles prepared have a zincblende structure. TEM observations showed that the ZnS nanoparticles are in a spherical form with an average diameter of 40 nm. XPS results proved that, for our sample, the binding energies of Zn 2p and S 2p are the same as those of bulk single-crystal, but the full widths at half maximum of the XPS peaks are larger than those of bulk single-crystal. Received: 22 September 1997/Accepted: 5 January 1998  相似文献   

6.
Core–shell CdS/ZnS nanoparticles in arachidic acid film were prepared through a novel Langmuir–Blodgett (LB) approach. Post-deposition treatment of the precursor LB multilayers of cadmium arachidate with H2S gas followed by intercalation of Zn2+ ions and further sulfidation result in the formation of CdS/ZnS nanoparticles in the LB film. The formation of these nanoparticles and resulting changes in layered structures were studied by FTIR and X-ray reflection measurements. The optical properties were studied using UV–vis absorption and photoluminescence spectroscopy. A red-shift in the absorption spectrum and enhancement of CdS excitonic emission together with reduction of surface states emission suggest that after the intercalation step, a thin layer of ZnS surrounds the CdS nanoparticles, thus forming a core–shell structure. Subsequent to the second sulfidation, a further red-shift in absorption suggests the formation of a thicker ZnS coating on CdS. Electron diffraction of CdS nanoparticles coated with thicker ZnS showed the diffraction patterns of only ZnS, as expected for core–shell structures.  相似文献   

7.
Fluorophosphate glasses doped with ZnS are studied. The properties of ZnS nanocrystals formed are determined using X-ray-diffraction analysis and optical spectroscopy. The size and the band-gap width of these crystals are determined by the Tauc method. It is shown that ZnS nanocrystals luminesce in the visible spectral region with a low (2–3%) absolute quantum yield.  相似文献   

8.
Ferromagnetic properties of Cu-doped ZnS: A density functional theory study   总被引:1,自引:0,他引:1  
Using plane-wave pseudopotential (PWPP) method, the magnetism and spin-resolved electronic properties of Cu-doped ZnS system are studied. Our calculations indicate that ferromagnetic (FM) state is ground state in Cu-doped ZnS. The FM coupling strength in ZnS doping with Cu fluctuates with the variation of distance between two dopants and the fluctuation gets larger with increase in distance. Room temperature ferromagnetism can be observed in Cu-doped ZnS with high dopant concentration. Formation energy calculation implies that the clustering effect is not obvious in Cu-doped ZnS. Thus, Cu-doped ZnS can be a promising dilute magnetic semiconductor (DMS), which promises to be free of magnetic precipitates.  相似文献   

9.
孟立建  钟国柱 《发光学报》1989,10(4):290-295
本文报导了不同浓度的金属铒和氟化铒掺杂的硫化锌薄膜交流电致发光(ACEL)的特性,并进行了比较。实验结果表明:ZnS:ErF3薄膜ACEL的最佳浓度(5×10-3g/g)低于ZnS:Er3+薄膜ACEL的最佳浓度(1×10-2g/g)。在ZnS薄膜中掺入稀土离子,随着浓度的增加,稀土离子之间发生交叉弛豫,这一过程与稀土离子周围环境有关,这正是ZnS:ErF3和ZnS:Er3+薄膜ACEL具有不同的最佳浓度的主要原因。  相似文献   

10.
The dielectric properties of nano-particles of ZnS have been studied over a temperature range from 300 to 525 K. The dielectric constant, dielectric loss and ac conductivity of the samples are larger than those of bulk ZnS crystals. Dielectric properties of composites consisting of nano-particles of Ag of different concentrations dispersed in nano-particles of ZnS have also been studied.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号