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Absolute density measurement of hydrogen atom in inductively coupled Ar/H2 plasmas using vacuum ultraviolet absorption spectroscopy
摘要： The absolute density measurement of atomic species such as hydrogen is crucial for plasma processing because of their strong chemical reactivity. In this work, to measure the hydrogen atom density in Ar/H2 inductively coupled plasmas (ICP), the self-absorption-applied vacuum ultraviolet absorption spectroscopy (VUVAS) is studied with a micro-hollow cathode H2/He discharge lamp (MHCL) emitting VUV light (Lyman alpha line; Lα 121.56 nm). The absolute density of hydrogen atoms in the ICP is investigated for various powers (50 W–850 W) in the low pressure region (30 mTorr–50 mTorr). The hydrogen density in remote plasma region is shown to vary from 2.1 × 1011 cm?3 to 1.25 × 1012 cm?3 with respect to plasma power.
关键词： VUV absorption spectroscopy,Low-pressure,Self-absorption,Hydrogen atom density,inductively coupled plasma
更新于2025-09-23 15:19:57
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Coal Discrimination Analysis Using Tandem Laser-Induced Breakdown Spectroscopy and Laser Ablation Inductively Coupled Plasma Time-of-Flight Mass Spectrometry
摘要： The contribution and impact of combined laser ablation inductively coupled plasma time of flight mass spectrometry (LA-ICP-TOF-MS) and laser induced breakdown spectroscopy (LIBS) were evaluated for the discrimination analysis of different coal samples. This Tandem approach allows simultaneous determination of major and minor elements (C, H, Si, Ca, Al, Mg, etc), and trace elements (V, Ba, Pb, U, etc.) in the coal. The research focused on coal classification strategies based on principle component analysis (PCA) combined with K-means clustering, partial least squares discrimination analysis (PLS-DA), and support vector machine (SVM) for analytical performance. Correlation analyses performed from TOF mass and LIBS emission spectra from the coal samples showed that most major, minor, and trace elements emissions had negative correlation with the volatile content. Suitable variables for the classification models were determined from these data. The individual TOF data, LIBS data, and the combined data of TOF and LIBS, respectively, as the input for different models were analyzed and compared. In all cases, the results obtained with the combined TOF and LIBS data were found to be superior to those obtained with the individual TOF or LIBS data. The nonlinear SVM model combined with TOF and LIBS data provided the best coal classification performance, with a classification accuracy of up to 98%.
关键词： Principal component analysis,Support vector machine,Partial least squares discrimination analysis,Laser-induced breakdown spectroscopy,K-means clustering,Coal discrimination,Laser ablation inductively coupled plasma time of flight mass spectrometry
更新于2025-09-23 15:19:57
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Advantages and Limitations of Laser-Assisted Mass Spectrometry for the Local Determination of the Trace Element Composition of Fluid Inclusions in Quarzites in the Bural-Sardyk Deposit (Vostochny Sayan, Buryatia)
摘要： The effect of laser radiation on the surface and volume of natural quartz of the Bural-Sardyk deposit (East Sayan, Buryatia) is studied. The influence of the main parameters of laser radiation with a wavelength of 213 nm (prefix NWR-213) and the properties of the sample on the results of elemental mass spectrometric analysis with inductively coupled plasma are established. The features of laser ablation of various microinclusions in quartz are considered. The main problems arising from the laser evaporation of fluid inclusions in quartzites for the quantitative determination of their chemical composition are indicated.
关键词： superquartzite,fluid inclusions,LA-ICP-MS,inductively coupled plasma mass spectrometry,laser ablation,quartz
更新于2025-09-23 15:19:57
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Study of fabrication and characterization of high power 850a?ˉnm vertical-cavity surface-emitting laser arrays
摘要： In this paper, we investigated high power selectively oxidation-confined AlxGa1-xAs/GaAs 850 nm vertical-cavity surface-emitting laser (VCSEL) and fabricated two-dimensional VCSEL arrays by photolithography using photo masks. Inductively coupled plasma (ICP) was employed to create the deep platform during the mesa process. The number of illuminating lasers has been designed at 60, 85, and 109 in the array. We further studied the influence of the number of illuminating lasers on the characteristics of the VCSEL devices. The threshold current was found to be increased significantly at about 93 mA, 118 mA, 149 mA, respectively. The injection current should produce a greater than the critical current density to meet the criteria for population inversion. However, the corresponding voltage remained almost unchanged, in the range of 1.57~1.63 V. The maximum optical output power was increased even more appreciably. It was measured at 448 mW, 592 mW, and 746 mW, respectively. On the other hand, the device equivalent series resistance was decreased with more illumination lasers in the array. The averaged resistance has been estimated at 4.16 Ω, 3.14 Ω, and 2.47 Ω, respectively. In addition, the optical spectrum became more dispersed, showing more lasing modes for the samples with the highest number in illumination lasers in the array. The peak wavelength full width at half-maximum was also slightly increased. The related electro-optical characteristics have been summarized and further discussed.
关键词： High power,Inductively coupled plasma,Laser array,Surface emitting
更新于2025-09-23 15:19:57
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Properties of Nitrogen/Silicon Doped Vertically Oriented Graphene Produced by ICP CVD Roll-to-Roll Technology
摘要： Simultaneous mass production of high quality vertically oriented graphene nanostructures and doping them by using an inductively coupled plasma chemical vapor deposition (ICP CVD) is a technological problem because little is understood about their growth mechanism over enlarged surfaces. We introduce a new method that combines the ICP CVD with roll-to-roll technology to enable the in-situ preparation of vertically oriented graphene by using propane as a precursor gas and nitrogen or silicon as dopants. This new technology enables preparation of vertically oriented graphene with distinct morphology and composition on a moving copper foil substrate at a lower cost. The technological parameters such as deposition time (1–30 min), gas partial pressure, composition of the gas mixture (propane, argon, nitrogen or silane), heating treatment (1–60 min) and temperature (350–500 ?C) were varied to reveal the nanostructure growth, the evolution of its morphology and heteroatom’s intercalation by nitrogen or silicon. Unique nanostructures were examined by FE-SEM microscopy, Raman spectroscopy and energy dispersive X-Ray scattering techniques. The undoped and nitrogen- or silicon-doped nanostructures can be prepared with the full area coverage of the copper substrate on industrially manufactured surface defects. Longer deposition time (30 min, 450 ?C) causes carbon amorphization and an increased fraction of sp3-hybridized carbon, leading to enlargement of vertically oriented carbonaceous nanostructures and growth of pillars.
关键词： vertically oriented graphene (VOG),Li-ion battery,roll-to-roll technology,inductively coupled plasma chemical vapor deposition (ICP CVD),supercapacitor
更新于2025-09-19 17:15:36
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Quantitative analysis of saindha salt using laser induced breakdown spectroscopy and cross-validation with ICP-MS
摘要： Saindha salt is considered to be more advantageous than the other edible salts for the patients suffering from diabetes, blood pressure and kidney diseases. To explore the constituent elements of this salt, laser induced breakdown spectroscopy (LIBS) has been exploited for its qualitative and quantitative analysis. The third harmonic (355 nm) of a Q-switched Nd:YAG laser has been used to produce the saindha salt plasma and the time integrated optical emission spectra were registered using a set of six miniature spectrometers covering the spectral range of 230–805 nm. The spectroscopic analysis of the emission spectra predominately revealed numerous neutral or singly ionized emission lines of Ca, Mg, Na, K, Fe, Sr, Si, Li and Al. The laser produced plasma was characterized by calculating the electron temperature from the Boltzmann plots and the electron number density from the Stark broadened line profile as a function of laser irradiance and distance from the target sample. The relative concentration of the constituent elements was extracted by the integrated line intensities of the strongest spectral line of each element using the self-calibration-LIBS (SC-LIBS) and one-line calibration free-LIBS (OLCF-LIBS) methods. For cross-validation, the LIBS results have been compared with that obtained from the inductively coupled plasma-mass spectroscopy (ICP-MS) showing good agreement.
关键词： inductively coupled plasma-mass spectroscopy,saindha salt,elemental analysis,one-line calibration-free LIBS,self-calibration-LIBS,plasma parameters
更新于2025-09-19 17:13:59
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Quantitative spatially resolved <i>post-mortem</i> analysis of lithium distribution and transition metal depositions on cycled electrodes <i>via</i> a laser ablation-inductively coupled plasma-optical emission spectrometry method
摘要： Diminishing the loss of performance of lithium ion batteries (LIBs) is a challenge that is yet to be ful?lled. Understanding of deterioration processes and mechanisms (i.e., so-called aging) requires analytically accurate examination of aged cells. Changes in the distribution of lithium or transition metals in the LIB cells can in?uence their cycle and calendar life signi?cantly. As electrochemically treated cells and especially their electrodes do not age homogeneously and the local electrochemistry (e.g. deposition patterns) is strongly dependent on surface properties, bulk analysis is not a satisfactory investigation method. Therefore, a surface sensitive method, namely laser ablation-inductively coupled plasma-optical emission spectrometry (LA-ICP-OES) is presented. LIB cells with lithium metal oxide LiNi1/3Co1/3Mn1/3O2 (NCM111) as cathode material and graphite as anode material are investigated using a 213 nm Nd:YAG laser.
关键词： graphite,aging,laser ablation-inductively coupled plasma-optical emission spectrometry,NCM111,LA-ICP-OES,LIBs,Nd:YAG laser,lithium ion batteries
更新于2025-09-19 17:13:59
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Optimization of Mesa Etch for a Quasi-Vertical GaN Schottky Barrier Diode (SBD) by Inductively Coupled Plasma (ICP) and Device Characteristics
摘要： The optimization of mesa etch for a quasi-vertical gallium nitride (GaN) Schottky barrier diode (SBD) by inductively coupled plasma (ICP) etching was comprehensively investigated in this work, including selection of the etching mask, ICP power, radio frequency (RF) power, ratio of mixed gas, ?ow rate, and chamber pressure, etc. In particular, the microtrench at the bottom corner of the mesa sidewall was eliminated by a combination of ICP dry etching and tetramethylammonium hydroxide (TMAH) wet treatment. Finally, a highly anisotropic pro?le of the mesa sidewall was realized by using the optimized etch recipe, and a quasi-vertical GaN SBD was demonstrated, achieving a low reverse current density of 10?8 A/cm2 at ?10 V.
关键词： quasi-vertical,inductively coupled plasma (ICP),GaN,dry etch,sidewall pro?le,mesa,Schottky barrier diode (SBD)
更新于2025-09-19 17:13:59
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Development of ZnO Nanoparticles as an Efficient Zn Fertilizer: Using Synchrotron-Based Techniques and Laser Ablation to Examine Elemental Distribution in Wheat Grain
摘要： Zinc (Zn) deficiency is an important problem worldwide, adversely impacting human health. Using a field trial in China, we compared the foliar-application of both ZnO nanoparticles (ZnO-NPs) and ZnSO4 on winter wheat (Triticum aestivum L.) for increasing the Zn concentration within the grain. We also used synchrotron-based X-ray fluorescence microscopy (μ-XRF) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to examine the distribution of Zn within the grain. We found that ZnO-NPs increase the Zn concentration in the wheat grain, increasing from 18 mg·kg-1 in the control up to 40 mg·kg-1 when the ZnO-NPs were applied four times. These grain Zn concentrations in the ZnO-NP-treated grains are similar to those recommended for human consumption. However, the ZnO-NPs were similar in their effectiveness to ZnSO4. When examining trace element distribution in the grain, the trace elements were found to accumulate primarily in the aleurone layer and the crease region across all treatments. Importantly, Zn concentrations in the grain endosperm increased by nearly 30-fold relative to the control, with this markedly increasing Zn within the edible portion. These results demonstrate that ZnO-NPs is a suitable fertilizer for increasing Zn within wheat grain and can potentially be used to improve human nutrition.
关键词： X-ray fluorescence microscopy (μ-XRF),foliar application,wheat,Zn biofortification,laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS),ZnO-NPs
更新于2025-09-19 17:13:59
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Iolite Based Bulk Normalization as 100% (m/m) Quantification Strategy for Reduction of Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Transient Signal
摘要： Iolite package draw more attention in laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) community in recent years due to its powerful data-handling capacity, excellent signal visualization and open source of calculation codes. In this study, the application of Iolite package was investigated for LA-ICP-MS elemental quantification, and a calculation code for the bulk normalization as 100% (m/m) strategy was compiled. We found that the spline interpolation approach was better than that of linear one for the correction of time-dependent instrument drift. BCR-2G as the quality material was used to assess the proposed code, and the results revealed that the code was practical and reliable. The analytical accuracy was influenced by the used calibration materials. TiO2, MgO, K2O and rare earth elements in BCR-2G were slightly off (5%–10%) when NIST SRM 610 as the calibrator. Cr and Mo were higher (10%–30%) than the recommended values when StHs6/80-G was used as the calibrator. The phenomena would be attributed to the matrix effect or the inaccurate values of corresponding calibrators. Three main sources for the LA-ICP-MS combined uncertainty were recognized, including the uncertainty of recommended values of analytes in calibration material, the uncertainty of measured intensity ratios in sample and the error in bulk normalization as 100% (m/m) strategy. A total of 50 elements in CGSG glass reference materials were quantified based on the proposed Iolite code. Major elements (except MnO, CaO and P2O5) matched well with the recommended values with a discrepancy of 5%, and the trace elements (except Cr, Ni, Zn, Ga, Mo and Sb) were agreement with the recommended values in 10%. The dataset reported in this study was helpful for the value certification of CGSG reference materials. Overall, the proposed Iolite code broadened the application of Iolite package in the reduction of LA-ICP-MS transient signal for the elemental determination.
关键词： CGSG reference material,Combined uncertainty,Laser ablation-inductively coupled plasma-mass spectrometry,Iolite package,Bulk normalization as 100% (m/m)
更新于2025-09-19 17:13:59