Nitrogen depth distribution, interface and structure analysis of SiNx layers produced by low-energy ion implantation

Thin silicon nitride (SiN _x ) layers with the stoichiometric N/Si ratio of 1.33 in the maximum of the concentration depth distributions of nitrogen were produced by implanting 10 keV¹⁵N ₂ ⁺ in 100 silicon at room temperature under high vacuum conditions. The depth distribution of the implanted isotope was measured by resonance nuclear reaction analysis (NRA), whereas the layer structure of the implanted region and the geometrical thickness of the layers were characterised by high resolution transmission electron microscopy (TEM). SiN _x layers with a thickness of about 30 nm were determined by NRA. Channeling Rutherford backscattering spectrometry was used to determine the disorder in the silicon substrate. Sharp interfaces of a few nanometers between the highly disordered implanted region and the crystalline structure of the substrate thickness were observed by TEM. The high thermal stability of SiN _x layers with N/Si ratios from under to over stoichiometric could be shown by electron beam rapid thermal annealing (1100 °C for 15 s, ramping up and down 5 °C/s) and NRA.     

Spectrophotometric and titrimetric determination of gallium in minerals and ores using semimethylthymol blue

The composition, overall stability constant and molar absorptivity of the chelate of gallium(III) ion with semimethylthymol blue, SMTB, were determined spectrophotometrically in acetate buffer (pH 4.5–5). A violet Ga(SMTB) chelate was formed with logarithmic overall stability constant of 18.0±0.1 (I=0.1) and molar absorptivity of 4.25×10⁴l mol^–1cm^–1 (_max 580 nm). SMTB is proposed as a new reagent for the spectrophotometric determination of micro-molar amounts of gallium(III). The colour development depends on time, temperature, pH and buffer species. The interference of different cations, anions and organic acids on gallium(III) determination was also investigated. Beer's law was obeyed for 3.5–31.3 gGa(III)/25ml (0.14–1.25 g ml^–1). SMTB was used for the spectrophotometric determination of gallium in different grade minerals and ores and the results were of acceptable error and relative standard deviation. Comparison between the two suggested methods and atomic absorption spectrometry for Ga(III) determination was carried out.     

Fluorine determination in the near surface region of solids using the19F(p,p′γ)19F resonance reaction

Fluorine surface contamination and depth profiles were studied using the¹⁹F(p, p')¹⁹F resonance reaction. Fluorine implanted silicon samples as well as ZrNb plates and Cr–Al layers after a HF-treatment have been examined. The resonance strengths of the narrow 1088 keV resonance were estimated.     

离子液体电沉积CuInxGa1-xSe2薄膜

采用循环伏安法(CV)对离子液体Reline中三元CuCl₂+InCl₃+SeCl₄体系和四元CuCl₂+InCl₃+GaCl₃+SeCl₄体系的电化学行为进行了研究。研究表明,In³⁺并入三元CIS(Cu-In-Se)薄膜体系和Ga³⁺并入四元CIGS(Cu-In-Ga-Se)薄膜体系均有两种途径：一是发生共沉积,二是直接还原。利用电感耦合等离子体发射光谱(ICP)和扫描电镜(SEM)对沉积电势、镀液温度和主盐浓度对CIGS薄膜组成、镀层表面形貌的影响进行了测试,结果表明通过工艺参数的选择可以控制Ga/(Ga+In)和CIGS薄膜组成并得到化学计量比为Cu_1.00In_0.78Ga_0.27Se_2.13的薄膜。     

Investigations in the ternary system Ti-Mo-N by means of EPMA and XRD

Arc-melted ternary Ti-Mo-N alloys were heat treated at 1423 K in order to evaluate the compositions of the equilibrium phases. The composition of the bcc phase-Ti _x Mo_1–x with respect to Mo and Ti was determined by electron probe microanalysis (EPMA) and lattice parameter measurements (XRD). In order to avoid the effects of plastic deformation caused by powdering the ductile-Ti _x Mo_1–x alloys, the lattice parameter measurements were carried out on small particles of the compact samples using Debye-Scherrer cameras. The EPMA and XRD results agree within the expected range of accuracy. Apparently the solubility of nitrogen in-Ti _x Mo_1–x is low and does not perceptibly affect EPMA and XRD results. The relationship between the lattice parameter and the nitrogen content of-TiN_1–x was applied to determine the composition of-TiN_1–x in equilibrium with-Ti_xMo_1-x No solid solubility of Mo in TiN_1–x could be detected. The tie lines at 1423 K between the two phases were established.     

Monte Carlo simulation of ion implantation into solids as a tool for the characterization of surface analytical reference materials

The physical and chemical prerequisites of ion implantation and their translation into a Monte Carlo calculation simulating the implantation process of high energy ions (300 keV) are described; calculations are extended to high dose implantation (up to 1×10¹⁸ ions cm^–2) taking into consideration various effects such as matrix change during implantation, cascade mixing, sputter erosion and relaxation of the target material.To check the suitability of such calculations for a characterization of implanted samples, the results of the calculations are compared with those obtained experimentally from implanted samples. As an example,P ⁺ is implanted into polycrystalline Al at various doses (110×10¹⁷ p ⁺ cm^–2), and depth profiles are taken by AES/Ar⁺-sputtering.The calculated and measured results agree better than 10% for both the depth and the concentration scale.     

Etching of metallic glasses for destructive determination of depth concentration profile by the PIXE method

The destructive technique for the determination of the depth concentration profile in metallic glasses of composition B₂₀Fe_xNi_80–x (for x from 40 to 70) is presented. The etching technique with HNO₃ has been proposed for removing surface layers of the thickness from 1 to 12 m. In the residual surfaces the concentration of Fe and Ni has been determined by the PIXE method with 1.4 MeV⁴He⁺ ions of the JINR Van de Graaff accelerator. With an emphasis on the solution of matrix effects in Fe–Ni systems, empirical correction methods have been applied.     

Morphology, structure and constitution of metastable single-phase Ti1-xAlxN films grown by reactive MSIP

Metastable, single phase, polycrystalline Ti_1–x Al _x N hard layers were deposited on HSS-substrates with reactive magnetron sputtering ion plating (MSIP). The substrate temperature was 400 °C, the bias –60 V, the argon pressure 1.2 Pa and the sputter power 6 W cm^–2. Compound targets with a Ti:Al ratio of 75/25, 50/50 and 25/75, expressed in at-%, were sputtered. The nitrogen reactive gas pressure during sputtering was 8.4 × 10^–2 Pa for the 7525 target and 1.08 × 10^–1 Pa for the 5050 and 2575 targets. The Ti_1–x Al _x N layers grew with x=0.26, 0.54 and 0.75, as determined with EPMA. Thin film XRD and HEED structure analysis showed that the Ti_0.74Al_0.26N layer had grown as B1 structure (a₀0.4214 nm) with [211] texture, the Ti_0.46Al_0.54N layer likewise as B1 structure (a₀0.4154) with [111] texture, but the Ti_0.25Al_0.75N as B4 structure (a₀0.317 nm and c₀0.5014 nm) with [110] texture. Pronounced columnar growth was observed with HR-SEM in the fractured surface of the cubic layers. The mean grain size, and consequently the surface roughness, diminished with increasing Al-content of the layer.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday     

The quantitative analysis of mixed crystals CuS x Se1-x with abrasive stripping voltammetry and a redetermination of the solubility product of CuSe and the standard potential of the Cu/CuSe electrode

Phase identifications and quantitative analyses of mixed crystals by means of abrasive stripping voltammetry are reported using covelliteklockmannite (CuS_xSe_1-x) and emplectite-chalcostibite (CuBi_x Sb_1-xS₂) mixed crystals as examples. The composition of CuS_xSe_1-x can be determined within a span of x=±0.03. Additionally the standard potential of the Cu/CuSe-electrode is measured to be E_Cu/CuSe= –0.749 V vs. Ag/AgCl.     

Structure of Electrical Double Layer on Liquid Pb–Ga Alloy in Aqueous Electrolytes

A new electrode, which is a liquid Pb–Ga alloy (0.06 at. % Pb), is developed and studied. It is shown that the alloy's double-layer characteristics dramatically differ from characteristics of a Ga electrode and are practically identical to characteristics of a Pb electrode. Hence, the Pb–Ga electrode in fact models electrochemical properties of a liquid Pb electrode. It is established that the metallic capacitance of the Pb–Ga electrode occupies an intermediate position between values of metallic capacitance of Ga and Hg electrodes, provided the metal–water chemisorption interaction is absent and the electrode charge is fixed. Hydrophilicity of the Pb–Ga electrode is substantially lower than hydrophilicity of a Ga electrode and coincides with hydrophilicity of an Hg electrode. It is shown that In–Ga, Cd–Ga, and Pb–Ga electrodes have close values of the electrochemical work function, and the chemisorption potential drop of the solvent in them increases in the series Pb–Ga < In–Ga < Cd–Ga with decreasing distance of closest approach of water molecules to the ionic core of the metal. The absorbability of anions at the Pb–Ga electrode increases in the series BF^– ₄= SO^2– ₄< Cl^–< Br^–< I^–.     

Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) of ZnS 1−x Se x Semiconductor Materials

Luminous zinc sulphide selenide crystals (ZnS_1–xSe_x) with an anion-gradient in the µm-range within the crystal were quantitatively investigated by LA-ICP-MS. Reference standard crystals were synthesized by chemical vapour transport reaction and characterized by µ-XRF, SEM, PIXE, RBS and solution ICP-MS. Values from several analytical methods were then combined to describe the concentration in the reference crystals. Using these crystals, calibration curves with high correlation coefficients could be obtained for laser ablation ICP-MS determination of elemental concentrations. The gradient determined afterwards in the zinc sulphide selenide sample crystals was in the order of 30wt% in Se-content within an 800µm distance. This shows the promising capabilities of LA-ICP-MS in the field of elemental quantification in the µm-range.     

离子液体电沉积CuIn_xGa_(1-x)Se_2薄膜(英文)

采用循环伏安法(CV)对离子液体Reline中三元CuCl2+InCl3+SeCl4体系和四元CuCl2+InCl3+GaCl3+SeCl4体系的电化学行为进行了研究。研究表明,In3+并入三元CIS(Cu-In-Se)薄膜体系和Ga3+并入四元CIGS(Cu-In-Ga-Se)薄膜体系均有两种途径:一是发生共沉积,二是直接还原。利用电感耦合等离子体发射光谱(ICP)和扫描电镜(SEM)对沉积电势、镀液温度和主盐浓度对CIGS薄膜组成、镀层表面形貌的影响进行了测试,结果表明通过工艺参数的选择可以控制Ga/(Ga+In)和CIGS薄膜组成并得到化学计量比为Cu1.00In0.78Ga0.27Se2.13的薄膜。     

Sensitive spectrophotometric determination of gallium with eriochrome Cyanine R and cetyltrimethylammonium ions

Summary A new sensitive, spectrophotometric determination of gallium, based on the ternary gallium-Eriochrome Cyanine R-cetyltrimethylammonium system has been developed. At _max=588 nm the molar absorptivity is 1.20×10⁵l·mole^–1·cm^–1. The maximum absorbance is attained in 5 min in the presence of a 10-fold molar ratio of Eriochrome Cyanine R and an approx. 50-fold ratio of cetyltrimethylammonium bromide (to Ga). Citrate, EDTA and to a lesser extent tartrate, interfere. Interference by metals can be eliminated by a preliminary extraction of gallium with di-isopropyl ether from 7 M hydrochloric acid in the presence of ascorbic acid as reductant. The results for gallium (at a concentration level of 1×10^–4%) in aluminium metal and chloride indicate good precision and accuracy.

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Empfindliche spektrophotometrische Bestimmung von Gallium mit Eriochromcyanin-R- und Cetyltrimethylammonium-Ionen

Zusammenfassung Ein neues, empfindliches spektrophotometrisches Verfahren zur Galliumbestimmung wurde ausgearbeitet. Es beruht auf der Verwendung des ternären Systems Gallium — EriochromcyaninR — Cetyltrimethylammonium. Bei _max=588 nm beträgt die molare Extinktion 1,20·10⁵ 1·Mol^–1·cm^–1. Die maximale Absorption wird innerhalb von 5 min bei Gegenwart der 10fachen molaren Menge EriochromcyaninR und der etwa 50fachen Menge Cetyltrimethylammoniumbromid erreicht. Citrat, ÄDTA und in geringerem Maß Tartrat stören. Störende Wirkung durch Metalle kann durch vorhergehende Extraktion des Galliums mit Diisopropyläther aus 7 M Salzsäure in Gegenwart von Askorbinsäure als Reduktionsmittel vermieden werden. Die Ergebnisse (im Konzentrationsbereich von 10^–4% Ga) in metallischem Aluminium und AICI₃ sind genau.

     

Nucleation of Titania Nanocrystals in Silica Titania Waveguides

SiO_{2(1 – x)}-TiO_2(x) monomode waveguides at 632.8 nm, with x in the range 0.07–0.2 and thickness of about 0.4 m, were deposited on silica substrates by a dip-coating technique. Nucleation of TiO₂ nanocrystals and the growth of their size by thermal annealing up to 1300°C were studied by waveguided Raman scattering in the SiO_2(0.8)-TiO_2(0.2) composition. In the low frequency region (5–50 cm^–1) of the VV and HV polarized Raman spectra the symmetric and quadrupolar acoustic vibrations are observed. The mean size of the titania particles are obtained from the frequencies of the Raman peaks. The results are compared with those obtained from the measure of the linewidths in the X-ray diffraction spectra. Nanocrystals with a mean size in the range 4–20 nm are obtained by thermal annealing in a corresponding range of 700–1300°C.     

Electrochemical Intercalation of Lithium into Graphite in Acetonitrile Solutions: The Effect of the Anion Nature

Effect of the anion nature on the cathodic intercalation of lithium into graphite is studied. The duration of a discharge process and the capacity of Li _x C₆ electrodes increase in the row Cl^– HSO₄ ^– < ClO₄ ^– < SCN^–. The highest negative potential of an Li _x C₆ electrode is reached when lithiating in an LiSCN non-aqueous solution. X-ray diffraction and microstructure analyses confirm the presence in the electrode's upper layers of predominantly layered compounds Li _x C₆A _y , where A is anion. In deep layers, the principal intercalation product is Li _x C₆.     

Die Systeme Nickel—Selen und Kobalt—Nickel-Selen

Zusammenfassung Das System Ni–Se wurde thermisch und röntgenographisch untersucht und aus den Resultaten und aus Literaturangaben das Phasendiagramm aufgestellt. Die Hochtemperaturphase -Ni₃Se₂ zersetzt sich peritektisch bei 785 °C, die Verbindung Ni₆Se₅ peritektoidisch bei 647,5 °C. Die B8-(NiAs-)Phase Ni_1–x Se hat einen kongruenten Schmelzpunkt bei 53,5 At% Se und 959 °C und eine maximale Phasenbreite von 50,5 At% Se (785 °C) bis 56,8 At% Se (856 °C). NiSe₂ zerfällt peritektisch bei 853 °C in Ni_1–x Se und eine Se-reiche Schmelze. In Schmelzen mit mehr als 68,0 At% Se tritt oberhalb 856 °C eine Mischungslücke auf. Röntgenographisch konnte die Existenz der vier Verbindungen -Ni₃Se₂, Ni₆Se₅, Ni_1–x Se und NiSe₂ bestätigt werden.Im Dreistoffsystem Co–Ni–Se wurden drei Schnitte untersucht. In den quasibinären Schnitten zwischen den B8-Phasen Ni_1–x Se und Co_1–x Se und zwischen den C2-Phasen NiSe₂ und CoSe₂ sind die Legierungen sowohl im flüssigen als auch im festen Zustand vollkommen mischbar. In beiden Schnitten fallen die Liquidus- und Solidustemperaturen kontinuierlich von der Co-zur Ni-Seite ab. Die ternäre Phase (Co_1–y Ni _y )₁₁Se₈ ist bei 400 °C zwischen 0,9>y>0,5 stabil.

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The systems nickel—selenium and cobalt—nickel—selenium. Transition metal-chalcogen systems, II Übergangsmetall-Chalkogensysteme, 2. Mitt.

The Ni–Se system was investigated by X-ray and thermal analyses and from the results and from published data the Ni–Se phase diagram was constructed. The high temperature phase -Ni₃Se₂ decomposes peritectically at 785°C, the compound Ni₆Se₅ peritectoidically at 647.5°C. The B8 (NiAs) phase Ni_1–x Se has a congruent melting point at 53.5 at% Se and 959°C and a maximum range of homogeneity between 50.5 at% Se (785 °C) and 56.8 at% Se (856 °C). NiSe₂ decomposes peritectically at 853 °C into Ni_1–x Se and a Se-rich melt. Melts with more than 68.0 at% Se exhibit above 856 °C a miscibility gap. X-ray investigations confirmed the existence of the four compounds -Ni₃Se₂, Ni₆Se₅, Ni1– xSe, and NiSe₂.Three sections of the ternary system Co–Ni–Se were investigated. Alloys of the quasibinary sections between the B8 phases Ni_1–x Se and Co_1–x Se and between the C2 phases NiSe₂ and CoSe₂ are completely miscible in the liquid as well as in the solid state. The liquidus and the solidus temperatures in these sections drop continuously from the Co-to the Ni-side of the diagram. The ternary phase (Co_1–y Ni _y )₁₁Se₈ is stable at 400 °C between 0.9<y<0.5.

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Mit 5 Abbildungen     

Mechanism of oxidation of selenium(IV) by cobalt(III) in perchloric acid — a kinetic study

Summary The kinetics of Co^III oxidation of Se^IV have been studied in aqueous HClO₄. The order with respect to Co^m is two the order with respect to Se^IV is one at low concentrations; two at high concentrations. The latter variation is attributed to the greater reactivity of the Se^IV dimier A mechanism involving complexation between oxidant and substrate is proposed. [CoOH]²⁺ is presumed to be the reactive Co^III species and H₂SeO₃ and HSeO ₃ ^– to be those of Se^IV. At 25° C, E_a, H and S for the monomeric path are 125.6±4.0 kJ mol^–1, 122.1±3.8 kJ mol^–1 and 206±12 JK^–1 mol^–1 respectively and those for the dimeric path are 88.6±3.6 kJ mol^–1, 85.9±3.4 kJ mol^–1 and 62.6±11.3 JK^–1 mol^–1 respectively.     

Crystalline Inclusions Formed in C+N+BF2 Coimplanted on Silicon (111)

In the present work, high-doses (10¹⁷–10¹⁸cm^–2) of carbon, nitrogen, and boron (BF₂⁺) ions were coimplanted on silicon (111) substrates at 21, 25 and 77keV, respectively. Two series of samples have been implanted (series A and B) and subsequently annealed. Series A samples have been implanted at room temperature and treated one minute by rapid thermal annealing (RTA) and 3 hours at 1200°C. Series B samples have been implanted at 600°C and subsequently annealed at 1200°C during 3 hours. The annealing in both series has been carried out in N₂ at atmospheric pressures.The structure of the buried layers has been determined by conventional and high resolution transmission electron microscopy (CTEM and HRTEM). Polycrystalline silicon and new crystalline phases are observed by electron diffraction patterns. The polycrystalline silicon inclusions have been confirmed from analysis of HRTEM images.     

New Layered Polymer [{Mn(H2O)3}2{Re6Se8(CN)6}] · 3.3H2O: Synthesis and Properties

The [{Mn(H₂O)₃}₂{Re₆Se₈(CN)₆}] · 3.3H₂O complex was produced on slow evaporation of an aqueous solution containing the salt of a cluster complex K₄Re₆Se₈(CN)₆ · 3.5H₂O and a 23-fold excess of Mn²⁺. The cluster complexes [Re₆Se₈(CN)₆]^4– are linked in a crystal into the charged coordination layers [{Mn(H₂O)₃}₄{Re₆Se₈(CN)₆}₃]^4– ₂ through the Mn²⁺ cations. The Mn²⁺ cations are coordinated in a layer by three cyano nitrogen atoms of the cluster complexes; the Mn–N bond lengths are 2.13(4) and 2.21(2) Å. Each [Re₆Se₈(CN)₆]^4– anion is bonded to three manganese cations Mn(1). The anions are bonded additionally to the Mn(2) cations disordered over two close positions.     

Studies on the voltammetric behaviour of salicyl fluorone and gallium-salicyl fluorone complex

In the NH₄Cl supporting electrolyte, within the pH range from 1 to 5, an irreversible adsorptive reducing wave of salicyl fluorone(SAF) was obtained. The electrode process was verified as follow: On the surface of mercury electrode, the adsorption of SAF obeys Frumkin isotherm.In 0.2 mol/l potassium hydrogen phthalate/HCl buffer solution, at pH 3.0, the sensitive adsorptive complex wave of Ga-SAF was obtained by linear sweep voltammetry. The composition of the electroactive complex was determined as Ga:SAF = 11. The peak height of the complex is proportional to the concentration of Ga(III) in the range of 1.5 × 10^–9 to 6.0 × 10^–7 mol/l, the detection limit is 1.0× 10^–9 mol/l. The proposed method has been applied to the determination of gallium content in aluminium alloys.