University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

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Classification: Industrial -> semiconductor

Citations 3

"A Flow Injection Flame-atomic Absorption Spectrometry System For The Determination Of The Real Stoichiometry Of Small CuInSe2 Semiconductor Crystals"
Fresenius J. Anal. Chem. 1996 Volume 354, Issue 2 Pages 184-187
A. Matousek Abel de la Cruz, J. L. Burguera, M. Burguera, S. Wasim, C. Rivas

Abstract: A method for the rapid determination of the real stoichiometry of small CuInSe, semiconductor crystals is presented. The powdered crystal samples have been weighed and acid dissolved in a closed dissolution system connected to a FI manifold for flame atomic absorption spectrometry (AAS) determination. The accuracy has been assessed by comparing the results obtained with those by conventional AAS, and by analyzing CuInSe2 polycrystals of known stoichiometry. The results obtained with the proposed method are in a good agreement with the expected values. The method alloys the dissolution of the crystals without any detectable loss of selenium and has been applied to the analysis of small samples of CuInSe2 monocrystals as a method for routine monitoring during the development of synthesis methods and in homogeneity studies of the crystal ingots. Finely ground CuInSe2 (3 mg; I) were dissolved in 1 mL 65% HNO3 and the solution was diluted to 10 mL with water in a closed dissolution system connected to a flow injection manifold (illustrated). Portions (120 µL) were diluted (1:10) with water (5 ml/min) in a dispersion coil (48.5 cm x 1 cm i.d.) and transferred to an AAS operated with air-acetylene burner gas and a nebulizer aspiration rate of 6 ml/min. Cu, In and Se were determined with lamp currents of 4 mA at 324.8 nm, 5 mA at 303.9 nm and 10 mA at 196 nm and slit widths of 0.7, 0.7 and 2 nm, respectively. Calibration graphs were linear from 5-80, 25-400 and 20-400 mg/l, respectively, for Cu, In and Se. The method was compared with the conventional open dissolution and direct batch aspiration procedure. RSD were 1.8-2.9 and 2.2-3.6%, respectively, for Cu and In were similar for both procedures but the RSD for Se were lower, 2.9-3.2% vs. 4.5-5%.
Copper Indium Selenium Spectrophotometry Method comparison Process monitoring Stoichiometry

"Optimization Of ET-ICP-MS Conditions For The Determination Of Multi-elements In Semiconductor-grade Acids"
Fresenius J. Anal. Chem. 1996 Volume 356, Issue 1 Pages 31-36
L. Samuel Contact Information, Katsuhiro Nakagawa and Tetsuya Kimijima

Abstract: Sample solutions (1-50 µL) were placed in graphite cups held in a ring-shaped graphite holder. The ET heating cycles were optimized for the cations of Cr(III), Mn(II), Al(III) and Na(I) singly, with Ar (1.07 L/min) as carrier gas to the ICP-MS detector. The Ar plasma-gas flow rate was 0.5 l/min and the cooling gas flow rate was 15 L/min. Maximum intensity and minimum RSD were achieved at vaporization temperatures of 3000°C for Cr and Al, 2800°C for Mn and 2750°C for Na, with vaporization times of 6-15 s. Compromise conditions of 2950°C for 6 s were chosen for the simultaneous determination of all four metals. Calibration graphs (25 µL injections) were linear for 0.5-3 ng/ml of each. The method was applied to the analysis of concentrated HCl that had been used for cleaning silicon wafers. Recoveries of 1 and 2 ng/mL of the four metals added to HCl were 95.5-117.7%. The detection limits, calculated as the surface atom concentration x 10^10/cm2 ranged from 0.002-0.58 for the single-element conditions and 0.002-1.48 for the compromise multi-element conditions, which compared very favourably with the detection limits obtained by flow injection ICP-MS.
Chromium(III) Manganese(II) Aluminum(III) Sodium(I) Mass spectrometry Method comparison Optimization

"Electrothermal Atomic Absorption Spectrometric Determination Of Lead In High-purity Reagents With Flow Injection Online Microcolumn Preconcentration And Separation Using A Macrocycle-immobilized Silica Gel Sorbent"
Spectrochim. Acta B 1996 Volume 51, Issue 14 Pages 1875-1889
Michael Sperling*, Xiu-ping Yan and Bernhard Welz

Abstract: Diagrams and a table of the valve sequence of the manifold are presented; it incorporated a 50 µL conical microcolumn of Pb-02 macrocycle-immobilized silica gel (100 µm; IBC Advanced Technologies, American Fork, UT, USA) on which Pb2+ was collected (efficiency 77%) for 1 min and from which it was eluted with 36 µL of 35 mM EDTA of pH 10.5 and propelled by air to an AS-70 furnace autosampler for Zeeman AAS with use of a transversely heated graphite atomizer (heating program tabulated). The enhancement factor was 77, which led to a detection limit of 0.4 ng/l. The RSD (n = 10) at 300 ng/l was 2.7%. The only interference was from >2000-, >20 000- and >200 000-fold levels of Ba2+, Sr2+ and K+ with respect to the Pb2+. The method was suitable for application also to semiconductors and other high-purity industrial materials.
Lead Spectrophotometry Silica gel Immobilized reagent Interferences Preconcentration