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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 article, the authors studied the steady current field distribution under the configuration of van der Pauw method for resistivity measurement in a diamond anvil cell and obtained the theoretical accuracy curve of the van-de-Pauw method.
Abstract: Using finite element analysis, the authors studied the steady current field distribution under the configuration of van der Pauw method [L. J. van der Pauw, Philips Tech. Rev. 20, 220 (1958)] for resistivity measurement in a diamond anvil cell. Based on the theoretical analysis, the authors obtained the theoretical accuracy curve of the van der Pauw method. This method provides accurate determination of sample resistivity when the ratio of sample thickness to its diameter is less than 0.45. They found that the contact area between electrode and sample is a key factor in the resistivity measurement accuracy and its size is dependent on the sample diameter for a given measurement accuracy.
17 citations
TL;DR: In this article, a straightforward extension of the van der Pauw calculation is presented, which allows a determination of the Hall coefficient from quantities measured in one field direction only, and is used for the measurement of resistivities and Hall coefficients.
Abstract: The van der Pauw geometry has been widely used for the measurement of resistivities and Hall coefficients. Although the measurement of a Hall coefficient requires a finite magnetic field, it should be noted that van der Pauw’s expression is valid only in the limit of zero field; in addition to the Hall contribution, measurements in a finite magnetic field generally include a term associated with field‐induced changes in the longitudinal resistivity. Although a simple solution to this problem entails taking the difference between readings in opposite field directions, there are circumstances where this may be impractical. In this note we present a straightforward extension of the van der Pauw calculation which allows a determination of the Hall coefficient from quantities measured in one field direction only.
17 citations
TL;DR: In this paper, the same growth conditions were applied to ZnSnAs2 thin films and the transport properties were measured from 5 K up to room temperature, showing that the chalcopyrite and sphalerite phases were present.
Abstract: ZnSnAs2 thin films were prepared by molecular beam epitaxy (MBE) on semi-insulating (001) InP substrates using the same growth conditions as previously reported. High-resolution X-ray diffractometry (HRXRD) and Raman spectroscopy studies suggest the presence of both the chalcopyrite and sphalerite phases. The transport properties were measured from 5 K up to room temperature. We observed a pronounced peak in the Hall coefficient temperature dependence curve at ~130 K, similar to those observed only from chalcopyrite-phase bulk ZnSnAs2 in earlier studies. A hole concentration of p = 5.98 ×1018 cm-3, hole mobility of µ= 23.61 cm2/(Vs) and resistivity of ρ= 4.43 ×10-2 Ωcm were obtained at room temperature.
17 citations
TL;DR: In this paper, the electronic conductivity of polypyrrole−dodecyl benzene sulfonate (PPy−DBS) was characterized as function of the redox level.
Abstract: The electronic conductivity of the electroactive polymer polypyrrole−dodecyl benzene sulfonate (PPy−DBS) has been characterized as function of the redox level. The polymer was synthesized with different isomers of the dopant anions: the common mixed DBS tenside and three well-defined synthetic dodecyl isomers (with the benzene group at positions 1, 2 and 6). The conductivity was measured both by van der Pauw measurements on PPy−DBS in the oxidized, dry state as function of temperature, and by electrochemical impedance spectroscopy as function of potential in 0.1 M NaCl aqueous electrolyte. These investigations demonstrate that even minor differences in the dopant anion can cause significant changes in the physical properties of the electroactive polymer. The highest conductivities (σ25 = 39 Scm-1) are obtained by the (6D)BS isomer, perhaps because the branching leads to denser packing and therefore smaller hopping distances. This was supported by X-ray measurements. Synthesis at lower temperatures genera...
17 citations
TL;DR: In and Sb were used as n-type and p-type dopants, respectively, for growing a series of undoped and doped CdTe films as discussed by the authors.
Abstract: Photoassisted molecular‐beam epitaxy (PAMBE) has been employed to grow a series of undoped and doped CdTe films. In and Sb were used as n‐type and p‐type dopants, respectively. The PAMBE‐grown epilayers exhibit outstanding electrical, optical, and structural properties as determined by van der Pauw Hall‐effect, low‐temperature photoluminescence, and double‐crystal x‐ray rocking curve measurements, respectively.
17 citations