The concept of constant emission yield in GDOES

This review paper describes the evolution of the quantification procedure for compositional depth profiling (CDP) in glow discharge optical emission spectrometry (GD-OES), based on the constant emission yield concept. The concept of emission yield (EY) is defined and ways of measuring it experimentally are discussed. The history of the development of quantitative CDP is reviewed, which shows that all of the different approaches depend on the assumption that the EY is essentially a matrix-independent quantity. Particular emphasis is placed on the dependence of the EY on the plasma parameters of current, voltage, power and pressure. In short, impedance changes (current voltage) can significantly affect the emission yield and should either be corrected mathematically or the impedance should be kept constant by pressure regulation in order to obtain reliable results from GDOES CDP. On the other hand, the effect of varying the pressure on the emission yield can be considered to be minor within the limits of practical operating conditions for most CDP applications. It is worth, however, bearing in mind that varying the discharge pressure has a significant effect on the plasma processes, and does affect the emission yield when these variations are large. The experimental results obtained for the emission yield are related to the results from theoretical model calculations published on the subject.     

Are cluster ion analysis beams good choices for hydrogen depth profiling using time‐of‐flight secondary ion mass spectrometry?

For more than three decades, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) has been used for elemental depth profiling. In recent years, cluster primary ion sources (principally, C₆₀⁺, Bi_n⁺, and Au_n⁺) have become widely available, and they can greatly enhance the signal intensity of molecular ions (10–1000 times). Understanding the performance of cluster ion analysis beams used in elemental depth profiling can greatly assist normal ToF‐SIMS users in choosing the optimal analysis beam for depth profiling work. Presently, however, the experimental data are lacking, and such choices are difficult to make. In this paper, hydrogen and deuterium depth profiling were studied using six different analysis beams—25 keV Bi⁺, Bi₃⁺, Bi₅⁺, 50 keV Bi₃²⁺, 10 keV C₆₀⁺, and 20 keV C₆₀²⁺. The effort shows that cluster primary ions do enhance H^? and D^? yields, but the enhancement is only about 1.5–4.0 times when compared to atomic Bi⁺ ions. Because the currents of atomic ion analysis beams are much stronger than the currents of cluster ion analysis beams for most commercial ToF‐SIMS instruments, the atomic ion analysis beams can provide the strongest H^? and D^? signal intensities, and may be the best choices for hydrogen and deuterium depth profiling. In addition, two representative nuclides, ³⁰Si and ¹⁸O, were also studied and yielded results similar to those of H^? and D^?. Copyright © 2011 John Wiley & Sons, Ltd.     

A selective metabolite array for the detection of phosphometabolites

Immobilised metal ion affinity (IMA) has been traditionally used specifically for the separation of phosphorylated proteins and nucleic acids, in proteomics and genomics, respectively. This report describes the novel application of IMA in metabolomics for the development of metabolite arrays to detect phosphometabolites using a plasma polymer-modified surface. Immobilisation of gallium, zirconium, cobalt, copper, zinc, nickel, iron, and chromium to acrylic acid plasma polymer followed by subsequent exposure to metabolites (phospho- and non-phosphometabolites) was investigated. Results analysed using ToF-SIMS suggests that gallium and zirconium exhibit higher phosphometabolite affinity and specificity compared to other metals, and can be used to develop metabolite arrays for the detection of phosphometabolites.     

高压射频等离子体增强化学气相沉积制备高效率硅薄膜电池的若干关键问题研究

报道了采用高压射频等离子体增强化学气相沉积(RF-PECVD) 制备高效率单结微晶硅电池和非晶硅/微晶硅叠层电池时几个关键问题的研究结果, 主要包括: 1)器件质量级本征微晶硅材料工艺窗口的确定及其结构和光电性能表征; 2)孵化层的形成机理以及减小孵化层的有效方法; 3)氢稀释调制技术对本征层晶化率分布及其对提高电池性能的作用; 4)高电导、高晶化率的微晶硅p型窗口层材料的获得, 及其对减小微晶硅电池p/i界面孵化层厚度和提高电池性能的作用等. 在解决上述问题的基础上, 采用高压RF-PECVD制备的单结微晶硅电池效率达8.16%, 非晶硅/微晶硅叠层电池效率11.61%.     

Doping of nuclear tracks with fullerene solution

Latent nuclear tracks in polymers can occasionally be doped with fullerene solution. A new technique - ‘Fullerene Tracer Profiling’, FTP - allows us to verify the success of the doping procedure by determining the fullerene depth distribution along the tracks. The basic principle of FTP is described, and first examples are given. Fullerene solution is found to penetrate into ion tracks in polyimide, but not into tracks in polypropylene, or into unirradiated polyimide or polypropylene foils.     

Electron binding energies in the study of adsorption by photoelectron spectroscopy: The reference level problem

There has been much discussion in the literature concerning the definition of a suitable reference level for electron binding energies in solids and adsorbed species. The reference level in molecular photoelectron spectroscopy is the vacuum level at infinity; and, in order to calculate the total energy of the system, it is also the appropriate reference level for electron binding energies in solids. We show that for solids and adsorbates the vacuum level is not a chemically useful reference level. This is because the absolute binding energy is affected by electrostatic potentials which are unrelated to the local chemical bonding. It is concluded that there is no experimental energy level, to which adsorbate binding energies can be referenced, which allows one to make an absolute measurement of binding energy shifts due to surface interaction. Approaches to obtaining chemically meaningful binding energies from the photoelectron spectra of adsorbates are discussed.     

数字全息形貌测量的基本特性分析

 在对数字全息技术进行严格理论分析的基础上，本文指出随单个CCD像元的尺寸的减小可能被记录物体的横向尺寸将变大，所允许的纵向尺寸却变小；另一方面其系统误差和被测量值本身的大小成正比，和横向分辨率成反比。     

Depth-profiling of polymer laminates using fourier transform infrared (ATR) spectroscopy: The barrier film technique

We report FTIR-ATR spectra of a polymer laminate (PMMA/PVOH) at different base layer thicknesses and different angles of incidence on a ZnSe substrate. By varying this ‘barrier’ layer (of PMMA) we have demonstrated that different effective penetration depths into the PVOH are achieved, in very good agreement with the calculated electric fields as a function of distance away from the substrate surface. Such work forms the basis for depth profiling measurements in order to detect interfacial interactions between the polymer molecules. © 1994 John Wiley & Sons, Inc.