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Van der Pauw method
About: Van der Pauw method is a research topic. Over the lifetime, 1682 publications have been published within this topic receiving 25364 citations.
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TL;DR: In this paper, the authors performed a cAPCVD study of a TiO2/SnO2 system using a range of techniques such as X-ray diffraction (XRD), wavelength dispersive x-ray (WDX) spectroscopy, XPS, scanning electron microscopy (SEM), and ultra violet-visible (UV-vis) spectrographs.
Abstract: Combinatorial atmospheric pressure (cAP)CVD is used to deposit a film of graded composition from mainly TiO2 to TiO2/SnO2 to mainly SnO2. This is the first cAPCVD study of a TiO2/SnO2 system. The thin film is characterized using a range of techniques such as X-ray diffraction (XRD), wavelength dispersive X-ray (WDX) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and ultra violet-visible (UV-vis) spectroscopy. It is found that, at various positions on the film, there are intimate compositions of TiO2 and SnO2. The photocatalytic activity is examined via the degradation of a Resazurin-based ‘intelligent ink’ under 365 nm wavelength irradiation. The change in the concentration of the dye can be monitored by digital imaging alone. The results show how TiO2-rich regions are photocatalytically active, producing a maximum formal quantum yield of 3.32 × 10−4 molecules per absorbed photon. The sheet resistance is determined using a four-point probe via the van der Pauw method. The conductivity is highest in the SnO2-rich and thicker regions of the film, however some of the intimate composite regions of TiO2/SnO2 show both conductivity and photocatalytic activity.
13 citations
TL;DR: In this paper, the electrical activation of As in Si has been measured with spreading resistance profiling, four point probe, and van der Pauw methods, and an inactive meta-stable As solid solution was formed in the near-surface region after amorphous layer regrowth.
Abstract: Arsenic implants performed in Si at ultralow energy have been extensively studied with structural, chemical, and electrical analysis. The near-surface damage annealing and its influence on the electrical activation of ultrashallow As in Si as a function of the anneal ambient has been investigated. Double alignment medium energy ion scattering, high resolution transmission electron microscopy, and low energy secondary ion mass spectrometry have been used to assess the dopant behavior and crystal recovery in the near-surface regions. The electrical activation of As in Si has been measured with spreading resistance profiling, four point probe, and van der Pauw methods. Major redistribution of the dopant into the SiO2–Si interface region occurred during crystal regrowth of the damaged Si layer. An inactive meta-stable As solid solution was formed in the near-surface region after amorphous layer regrowth. Electrical activation of the dopant occurred upon dissociation of the As solid solution, when the dopant c...
13 citations
TL;DR: A two-sourced evaporation technique was used for deposition of cadmium telluride thin films onto scratch-free transparent glass substrates, using Cd and Te as two different evaporants as mentioned in this paper.
Abstract: A two-sourced evaporation technique was used for deposition of cadmium telluride thin films onto scratch-free transparent glass substrates, using Cd and Te as two different evaporants. Nine samples were deposited at three Te evaporation rates, that is, 6.5, 4.5, and 2.5 nm/s as a function of three substrate temperatures at 400, 300, and 200 °C respectively, keeping the Cd evaporation rate fixed at 2.7 nm/s. All the samples were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), optically by Lambda 900 UV/vis/NIR spectrophotometer and electrically, that is, DC electrical resistivity, by the van der Pauw method at room temperature. Content composition was investigated by energy-dispersive X-ray analysis. Strong mutually supporting effects on structure, morphology, optical transmission, reflection, and electrical resistivity were observed.
13 citations
TL;DR: In this paper, the authors used a sol-gel route as the cathode material for SOFC, and used methanol and acetyl acetone as solvent and chelating agent, respectively.
13 citations
TL;DR: In this article, thin polycrystalline SnO2 films were deposited on glass substrates by magnetron sputtering and the electrical, optical, and gas-sensing properties, as well as the structure and phase composition of the films, were studied.
Abstract: Thin polycrystalline SnO2 films were deposited on glass substrates by magnetron sputtering. Electrical, optical, and gas-sensing properties, as well as the structure and phase composition of the films, were studied. The electrical resistance of the films and the concentration and mobility of free charge carriers were determined by the four-point-probe and van der Pauw methods. The band gap and the type of optical transitions in the films were derived from optical absorption spectra. The sensitivity to toxic and explosive gases was measured. The composition, morphology, and crystal structure of the films annealed at 600°C were examined by X-ray diffraction and electron microscopy. The films were found to contain only a tetragonal SnO2 phase and have good crystallinity. The average grain size in the annealed films is 11–19 nm. A model of the electrical conduction in the polycrystalline SnO2 films is discussed.
13 citations