Flash Vacuum Thermolysis of 4H-3,1-Benzodithiin-4-thione: UV-Photoelectron Spectroscopy Characterization of Benzothiet-2-thione and Quantum Chemistry Studies

Abstract The p-n junction of a GaAs light emitting diode is fabricated using liquid phase epitaxy (LPE). The junction is grown on a Si doped (~1018/cm3) GaAs substrate. Intermittent yield loss due to forward voltage snapback was observed. Historically, out of specification forward voltage (Vf) parameters have been correlated to abnormalities in the junction formation. Scanning electron (SEM) and optical microscopy of cleaved and stained samples revealed a continuous layer of material approximately 2.5 to 3.0 urn thick at the n-epi/substrate interface. Characterization of a defective wafer via secondary ion mass spectroscopy (SIMS) revealed an elevated concentration of O throughout the region containing the defect. X-ray Photoelectron Spectroscopy (XPS) and Auger Electron Spectroscopy (AES) data taken from a wafer prior to growth of the epi layers did not reveal any unusual oxidation or contamination. Extensive review of the processing data suggested LPE furnace pressure was the obvious source of variability. Processing wafers through the LPE furnace with a slight positive H2 gas pressure has greatly reduced the occurrence of this defect.

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The Impact of UV Photoelectron Spectroscopy on the Field of Organic Optoelectronics—A Retrospective

Advanced Optical Materials ◽

10.1002/adom.202100227 ◽

2021 ◽

pp. 2100227

Author(s):

Selina Olthof

Keyword(s):

Photoelectron Spectroscopy ◽

Organic Optoelectronics ◽

The Impact ◽

Uv Photoelectron Spectroscopy

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Simultaneous Kinetics of Selenite Oxidation and Sorption on δ-MnO2 in Stirred-Flow Reactors

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18062902 ◽

2021 ◽

Vol 18 (6) ◽

pp. 2902

Author(s):

Zheyong Li ◽

Yajun Yuan ◽

Lin Ma ◽

Yihui Zhang ◽

Hongwei Jiang ◽

...

Keyword(s):

Rate Constant ◽

Photoelectron Spectroscopy ◽

Oxide Surfaces ◽

Kinetic Rate Constant ◽

Flow Reactors ◽

Mn Oxide ◽

Remediation Strategies ◽

Process Of Se ◽

Kinetics Of

Selenium (Se) is an essential and crucial micronutrient for humans and animals, but excessive Se brings negativity and toxicity. The adsorption and oxidation of Se(IV) on Mn-oxide surfaces are important processes for understanding the geochemical fate of Se and developing engineered remediation strategies. In this study, the characterization of simultaneous adsorption, oxidation, and desorption of Se(IV) on δ-MnO2 mineral was carried out using stirred-flow reactors. About 9.5% to 25.3% of Se(IV) was oxidized to Se(VI) in the stirred-flow system in a continuous and slow process, with the kinetic rate constant k of 0.032 h−1, which was significantly higher than the apparent rate constant of 0.0014 h−1 obtained by the quasi-level kinetic fit of the batch method. The oxidation reaction was driven by proton concentration, and its rate also depended on the Se(IV) influent concentration, flow rate, and δ-MnO2 dosage. During the reaction of Se(IV) and δ-MnO2, Mn(II) was produced and adsorbed strongly on Mn oxide surfaces, which was evidenced by the total reflectance Fourier transform infrared (ATR-FTIR) results. The X-ray photoelectron spectroscopy (XPS) data indicated that the reaction of Se(VI) on δ-MnO2 produced Mn(III) as the main product. These results contribute to a deeper understanding of the interface chemical process of Se(IV) with δ-MnO2 in the environment.

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The Growth and Characterization of Germanium-Carbon Alloy Thin Films

MRS Proceedings ◽

10.1557/proc-270-91 ◽

1992 ◽

Vol 270 ◽

Author(s):

Haojie Yuan ◽

R. Stanley Williams

Keyword(s):

Thin Films ◽

Photoelectron Spectroscopy ◽

Vacuum Chamber ◽

Optical Band Gap ◽

High Vacuum ◽

Optical Absorption Spectroscopy ◽

Alloy Thin Film ◽

New Materials ◽

X Ray

ABSTRACTThin films of pure germanium-carbon alloys (GexC1−x with x ≈ 0.0, 0.2, 0.4, 0.5, 0.6, 0.8, 1.0) have been grown on Si(100) and A12O3 (0001) substrates by pulsed laser ablation in a high vacuum chamber. The films were analyzed by x-ray θ-2θ diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), conductivity measurements and optical absorption spectroscopy. The analyses of these new materials showed that films of all compositions were amorphous, free of contamination and uniform in composition. By changing the film composition, the optical band gap of these semiconducting films was varied from 0.00eV to 0.85eV for x = 0.0 to 1.0 respectively. According to the AES results, the carbon atoms in the Ge-C alloy thin film samples has a bonding configuration that is a mixture of sp2 and sp3 hybridizations.

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