共查询到20条相似文献,搜索用时 31 毫秒
1.
A. Bergmaier G. Dollinger C. M. Frey T. Faestermann 《Fresenius' Journal of Analytical Chemistry》1995,353(5-8):582-584
Elastic recoil detection with heavy ions is a well suited method to measure depth profiles of light and medium heavy elements in thin films. Due to known Rutherford scattering cross sections and stopping powers of ions in matter, measurements can be quantified with an accuracy of about 1%. The transformation of energy spectra to quantitative elemental depth profiles, however, is generally a non trivial task and therefore a transofrmation algorithm has been developed based on a similar one for RBS analysis and realised in the program KONZERD. The transformation procedure allows a fast conversion from raw spectra to concentration profiles for classical ERD measurements as well as for high resolution measurements with a depth resolution better than 1 nm. 相似文献
2.
C. Jech 《Journal of Radioanalytical and Nuclear Chemistry》1976,30(2):457-461
It is well known that by the coordinated action of atoms arranged in rows and planes in the crystal lattice, the motion of
charged particles such as protons, alpha particles and heavier ions can be influenced so that their range in the single crystals
is considerably enhanced in low-index directions. A technique has been developed based on such enhanced penetration (channeling)
of radioactive atoms (220Rn) emitted by recoil with a 100 keV energy from a224Ra point source to record channeling patterns which show the crystal structure. The radioactive recoil atoms impinging from
this source on the surface of a single crystal penetrate deeper in places where their direction of impact is identical with
low index crystal directions and planes. These places can be visualized by autoradiography when having first stripped a thin
layer from the surface corresponding to the random range of the atoms. This technique is generally applicable in close packed
crystals and gives information about the crystal structure of very thin surface layers. 相似文献
3.
O. A. Rusu S. Dreve R. Cs. Begy D. C. Nita L. D. Bobos C. Cosma 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):241-245
Alpha spectrometry is an extremely useful and sensitive for detection of alpha-emitting nuclides. Contamination of the silicon
detectors for low-level alpha spectrometry by recoil nuclides is a serious problem in the measurement of alpha emitters decaying
to daughter nuclides with short half-lives. This unwanted contamination leads to decreased measurement sensitivity causing
a degradation of the limit of detection. The simplest method to prevent this radioactive contamination of detector is to use
a catcher film between the alpha source and the detector. In this work we describe the obtaining of the thin formvar films
as stopper foils for recoil nuclei and we investigated the influence of these films on alpha spectrometry parameters, as energy
shift (~30 keV) and resolution (~7%). No significant deterioration of the alpha spectrometry parameters was observed when
using thin formvar films. Using the ASTAR web databases, which calculate stopping powers for alpha particles, the thickness
of formvar films was estimated to be about 5.355 × 10−5 g/cm2. The measurements were performed with an ORTEC SOLOIST alpha spectrometer with PIPS detector. 相似文献
4.
以柠檬酸为配位剂,在酸性条件下采用化学浴沉积方法在FTO玻璃衬底上制得硫化铟薄膜,分别采用XRD、SEM、UV等手段对薄膜相结构、形貌和薄膜的透光率进行了表征。结果表明薄膜为立方结构的β-In2S3,薄膜均一连续,呈网状表面形貌,透光率随厚度增加而递减,带隙宽度介于2.5~2.6 eV之间。主要研究了配位剂的浓度对薄膜形成机理的影响,结果表明:柠檬酸浓度较低时,柠檬酸根与铟离子的配位平衡是整个反应的速控步骤;当柠檬酸浓度较高时,硫代乙酰胺与酸作用生成硫离子的反应是整个反应的速控步骤。 相似文献
5.
Bala T Prasad BL Sastry M Kahaly MU Waghmare UV 《The journal of physical chemistry. A》2007,111(28):6183-6190
The binding strength of the carboxylic acid group (-COOH) with different divalent metal ions displays considerable variation in arachidic acid (AA) thin films. It is considered that in AA thin films the metal ions straddle the hydrophilic regions of the stacked bilayers of AA molecules via formation of carboxylates. In this study first the uptake of different divalent cations in films of AA is estimated by atomic absorption spectroscopy (AAS). Through the amount of cation uptake, it is found that the strength of binding of different cations varies as Ca2+>Co2+>Pb2+>Cd2+. Variation in the binding strength of different ions is also manifested in experiments where AA thin films are exposed to metal ion mixtures. The higher binding strength of AA with certain metal ions when exposed individually, as well as the preference over the other metal ions when exposed to mixtures, reveal some interesting deviation from the expected behavior based on considerations of ionic radii. For example, Pb2+ is always found to bind to AA much more strongly than Cd2+ even though the latter has smaller ionic radius, indicating that other factors also play an important role in governing the binding strength trends apart from the effects of ionic radii. Then, to get a more meaningful knowledge regarding the binding capability, first-principles calculations based on density functional theory have been applied to study the interaction of different cations with the simplest carboxylic acid, acetic acid, that can result in formation of metal diacetates. Their electronic and molecular structures, cohesive energies, and stiffness of the local potential energy well at the cation (M) site are determined and attempts are made to understand the diversity in geometry and the properties of binding of different metal ions with -COOH group. We find that the calculated M-O bond energies depend sensitively on the chemistry of M atom and follow the experimentally observed trends quite accurately. The trends in M-O bond energies and hence the total M-acetate binding energy trends can actually be related to their molecular structures that fall into different categories: Ca and Cd have tetrahedral coordination; Fe, Ni, and Co exhibit planar 4-fold coordination; and Pb is off-centered from the planar structure (forming pyramidal structure) due to its stereochemically active lone pair of electrons. 相似文献
6.
Dollinger G Bergmaier A Faestermann T Frey CM 《Analytical and bioanalytical chemistry》1995,353(3-4):311-315
Elastic recoil detection (ERD) with energetic heavy ions (e.g. 60-120 MeV(127)I) is a suitable method to measure depth profiles of light and medium heavy elements in thin films. The advantages of this method are reliable and quantitative results and elementally and isotopically resolved depth profiles. A relative energy resolution of 0.07% has been measured in real ERD-experiments using the Q3D magnetic spectrograph at the Munich tandem accelerator and a large solid angle of detection of 5 msr. The good energy resolution allows atomic depth resolution near to the surface which has been obtained at flat and smooth carbon samples. A large solid angle of detection is necessary to measure a depth profile with the desired accuracy before the sample is significantly altered by the ion beam. As an example carbon profiles of thin carbon layers, prepared by a laser plasma ablation deposition process, have been investigated revealing the high depth resolution and its power to resolve elemental profiles at gradiated interfaces. 相似文献
7.
Väino Sammelselg Eero Rauhala Kai Arstila Alex Zakharov Jaan Aarik Arvo Kikas Juhan Karlis Aivar Tarre Anni Seppälä Jelena Asari Indrek Martinson 《Mikrochimica acta》2002,139(1-4):165-169
Titanium oxide and zirconium oxide thin films deposited on silicon substrates were characterised using electron probe microanalysis
(EPMA), Rutherford backscattering spectroscopy (RBS), time-of-flight elastic recoil detection analysis (TOF-ERDA) and scanning
photoelectron microscopy (SPEM). The composition and mass thickness of the films were determined and the results of different
methods compared. It was revealed that the synchrotron radiation used for SPEM studies caused considerable modification of
zirconia films grown at low temperatures. 相似文献
8.
G. Dollinger A. Bergmaier T. Faestermann C. M. Frey 《Fresenius' Journal of Analytical Chemistry》1995,353(3-4):311-315
Elastic recoil detection (ERD) with energetic heavy ions (e.g. 60–120 MeV127I) is a suitable method to measure depth profiles of light and medium heavy elements in thin films. The advantages of this method are reliable and quantitative results and elementally and isotopically resolved depth profiles. A relative energy resolution of 0.07% has been measured in real ERD-experiments using the Q3D magnetic spectrograph at the Munich tandem accelerator and a large solid angle of detection of 5 msr. The good energy resolution allows atomic depth resolution near to the surface which has been obtained at flat and smooth carbon samples. A large solid angle of detection is necessary to measure a depth profile with the desired accuracy before the sample is significantly altered by the ion beam. As an example carbon profiles of thin carbon layers, prepared by a laser plasma ablation deposition process, have been investigated revealing the high depth resolution and its power to resolve elemental profiles at gradiated interfaces. 相似文献
9.
磁控溅射制备的铜钒氧化物薄膜及其电化学性能 总被引:1,自引:1,他引:0
采用射频磁控溅射技术在硅基底上分别制备了无掺杂和掺杂Cu的氧化钒薄膜. X射线衍射(XRD)分析和扫描电子显微镜(SEM)观察表明, 无掺杂的薄膜为多晶V2O5, 掺杂Cu的薄膜为非晶态. X射线光电子能谱(XPS)分析结果表明, 掺杂Cu的薄膜为铜钒氧化物膜, 其中Cu离子表现为+2价, V离子为+4与+5价的混合价态. 随着Cu掺杂量的增大, +4价V的含量增加. 电化学测试结果表明, V2O5薄膜在掺杂Cu以后其放电容量有显著的提高, 其中Cu2.1VO4.4薄膜在100次循环后容量还保持为83.4 μA·h·cm-2·μm-1, 表现出较高的放电容量和较好的循环性能. 相似文献
10.
Silicon carbide thin films, prepared by carbonization of Si-wafers are analysed by Auger depth profiling. The influence of atomic mixing is simulated with a Monte Carlo model. By using mixing simulations the dependence of the two mixing parameters (width of the mixing zone and recoil depth) on ion beam energy, incidence angle and ion mass can be calculated. For comparison of the simulated data with Auger measurements an Auger electron escape depth correction is necessary. The simulated and -corrected data of several layer structures show good qualitative agreement with Auger depth profiles of thin carbonized SiC-layers.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday 相似文献
11.
《Surface and interface analysis : SIA》2006,38(1):1-5
Ion implantation techniques were used to study the effect of an MgO additive on the luminescence properties induced by Cu in ZnO thin films. Cu ions (accelerating voltage of 75 keV, dose of 4.5 × 1014 ions/cm2) were implanted at room temperature in nondoped and Mg‐doped ZnO thin films. After annealing, emissions in the visible region originating from Cu phosphor were observed at 510 nm in CVD‐ZnO and at 450 nm in Mg‐doped ZnO (MZO) thin films. The Cu depth profile shows distortion in the low‐concentration region of CVD‐ZnO. After the annealing, the Cu implant was homogenized in thin films, and then the Cu concentration was determined to be 1.5 × 1019 ions/cm3 in CVD‐ZnO and 5.6 × 1018 ions/cm3 in MZO thin films. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
12.
Bo-Hong Liu Yuan Tseh Lee Yi-Sheng Wang 《Journal of the American Society for Mass Spectrometry》2009,20(6):1078-1086
Utilizing synchronized dual-polarity matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, we found good
evidence of the incoherent production of positive and negative matrix ions. Using thin, homogeneous 2,5-dehydroxybenzoic acid
(DHB) matrix films, positive and negative matrix ions were found to appear at different threshold laser fluences. The presence
of molecular matrix ions of single charge polarity suggests that the existence of DHB ion-pairs may not be a prerequisite
in MALDI. Photoelectrons induced by the laser excitation may assist the production of negative DHB ions, as shown in experiments
conducted with stainless steel and glass substrates. At high laser fluences, the relative yield of positive and negative matrix
ions remained constant when homogeneous matrix films were used, but it fluctuated significantly with inhomogeneous crystal
morphology. This result is also inconsistent with the hypothesis that matrix ion-pairs are essential primary ions. Evidence
from both low and high laser fluences suggests that the productions of positive and negative matrix ions in MALDI may occur
via independent pathways. 相似文献
13.
随着薄膜材料的日益发展和新型薄膜材料的不断涌现,开发薄膜生长技术对于半导体和光电等科技领域的作用日益突出。本文主要介绍最近发展的聚合物辅助沉积从分子层面上控制生长高质量的薄膜材料。聚合物辅助沉积是一种生长高质量薄膜的化学水性溶液方法,将金属离子与聚合物通过络合、氢键或静电等方式形成一种均匀稳定的前驱体溶液,再经过超滤、成膜和热处理形成高质量的金属氧化物、金属碳化物、金属氮化物、金属单质、金属硫/硒化物等薄膜以及纳米粒子等化合物或复合功能材料。该方法中水溶性的聚合物能通过络合作用抑制金属离子的水解使得溶液稳定,并能精确控制薄膜的组分从而形成高质量的薄膜。该化学溶液方法的提出为科学技术领域提供了一种低成本和大面积制备薄膜的技术路线。本文最后总结和展望了聚合物辅助沉积法未来的挑战和发展方向。 相似文献
14.
由有机LB膜技术发展了一种制备组分、厚度可控的无机超薄陶瓷膜的方法.以Zr、 Y的β-二酮络合物的作为"表面离子"代替传统的亚相离子,沉积它们与花生酸的混合LB膜.并将它作为前驱物,经臭氧处理和热处理,成功制得了Y2O3稳定的立方相ZrO2超薄膜(YSZ).用X射线衍射(XRD)、 X射线光电子能谱(XPS)等手段研究了YSZ薄膜的相结构和其组成.结果表明,超薄陶瓷膜中Zr与Y的含量比率控制得很好,且形成Y2O3稳定的立方相ZrO2.说明这种方法可以成功地用来制备组分和膜厚均可控的纳米陶瓷膜. 相似文献
15.
S Matsuo N Sakaguchi E Obuchi K Nakano R C Perera T Watanabe T Matsuo H Wakita 《Analytical sciences》2001,17(1):149-153
Ni L- and Ti L-edge as well as Ti K-edge X-ray absorption experiments for TiO2 thin films and Ni-doped TiO2 thin films coated on glass plates were performed using synchrotron radiation to investigate the structures around Ni and Ti ions in the films. The obtained spectra were compared with the results of theoretical calculations. It has consequently been found that the spectral features were affected by a change in the oxidizing form of Ni ions due to hydrogen reduction, by the charge variation and/or slight orbital splitting of Ti ions, and by the magnitude of the interaction between the center Ti ion and neighboring Ti ions. 相似文献
16.
Zhu X Tang X Shi D Jian H Lei H Yeoh WK Zhao B Yang J Li Q Zheng R Dou S Sun Y 《Dalton transactions (Cambridge, England : 2003)》2011,40(37):9544-9550
Bi(2)Sr(3)Co(2)O(y) thin films are prepared on SrTiO(3) (100), (110) and (111) single crystal substrates using the sol-gel method. All the thin films are c-axis oriented regardless of the orientation of the substrate suggesting self-assembled c-axis orientation, and X-ray photoelectron spectroscopy results give evidence of coexistence of Co(3+) and Co(2+) ions in the derived films. Transmission electronic microscopy observations reveal that all samples are c-axis oriented with no obvious differences for different samples, and the c-axis lattice constant is determined as ~15 ? suggesting the misfit structure. A phenomenological thermodynamic phase diagram for self-assembled c-axis orientation is established for misfit cobaltate-based films using chemical solution deposition. All samples behave like semiconductors due to the coexistence of Co(3+)/Co(2+) ions, and the resistivity at 350 K is ~47, 39 and 17 mΩ cm for the thin films on SrTiO(3) (100), (110) and (111), respectively, whereas the Seebeck coefficient at 300 K is 97, 89 and 77 μV K(-1). The successful attainment of Bi(2)Sr(3)Co(2)O(y) thin films with self-assembled c-axis orientation will provide an effective prototype for investigation of growth mechanisms in complex oxide thin films with a misfit structure. 相似文献
17.
CoFe2-xRExO4(RE=Tb,Dy)纳米晶薄膜的化学合成及磁性 总被引:9,自引:0,他引:9
以溶胶-凝胶法制备了稀土铽或镝掺杂的钴尖晶石铁氧体纳米晶薄膜.考察了Tb或Dy的掺杂量及晶化条件对晶相的影响.结果表明,稀土离子的掺杂量x超过0.3时,样品很难形成尖晶石单相.原子力显微镜对纳米晶薄膜表面形貌的观测显示,溶胶-凝胶法制备的薄膜粒度可控制在20~50nm,且具有较高的表面平整度.对于厚度为200nm的薄膜,均方根粗糙度仅为4~5nm.磁特性研究发现,掺杂Tb或Dy的样品矫顽力明显提高. 相似文献
18.
As a new concept for the design of effective photocatalysts, an ion beam technology using accelerated metal ions, a metal ion implantation and an ionized cluster beam (ICB) method, have been applied to design unique photocatalysts. The metal ion implantation of TiO2 and Ti-containing zeolites with highly accelerated metal ions (V+, Cr+, etc.) is useful in designing photocatalysts that can operate efficiently under visible light irradiation. Also, an ICB method with a low acceleration energy is useful in preparing transparent TiO2 thin films on various types of substrates for the efficient photocatalytic degradation of pollutants diluted in water and air. The combination of the ICB method and metal ion implantation can develop the TiO2 thin films that are able to operate not only under UV light but also under visible light irradiation. 相似文献
19.
20.
A. P. Tikhonov O. N. Sorokina A. L. Kovarskii A. P. Solomatin A. V. Afonin P. P. Sinitsa 《Colloid Journal》2006,68(1):93-97
Experimental and theoretical EPR spectra of nanodispersed copper synthesized by the reduction of copper dichloride in aqueous solutions, thin films of electrolytic copper, and copper ions are analyzed. It is established that the reduction of copper dichloride in an aqueous solution in the presence of a surfactant yields copper nanoparticles. The EPR spectra are shown to be sensitive to the oxidation of copper nanoparticles in both an aqueous medium and in thin copper films prepared by electrolytic deposition. 相似文献