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.

Effect of Nb doping on the structural, morphological, optical and electrical properties of RF magnetron sputtered In2O3 nanostructured films

Abstract: Undoped and niobium (Nb) doped indium oxide (In2O3) thin films are prepared by radio frequency magnetron sputtering technique. The effect of Nb on the structural, morphological, optical and electrical properties of In2O3films are analyzed using techniques such as X-ray diffraction (XRD), micro-Raman spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy, UV–visible spectroscopy, spectroscopic ellipsometry, photoluminescence spectroscopy and Hall effect measurements. XRD analysis reveals that the as-deposited undoped and Nb doped films are polycrystalline in nature with cubic bixbyite structure. Raman analysis supports the presence of cubic bixbyite structure of In2O3in the films. XPS analysis shows a decrease of oxygen deficiency due to Nb and the existence of Nb as Nb4+ in the In2O3lattice. The band gap energy of the films increases with increase in Nb concentration. PL spectra reveal intense UV and visible emissions in all the films. Optical constants of the films are determined using spectroscopic ellipsometry. The thickness of films estimated using FESEM and ellipsometry are in good agreement. The carrier concentration, mobility and nature of carriers are measured using Hall measurement technique in Van der Pauw configuration at room temperature. (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Electrical and optical properties of InP grown by metalorganic vapor phase epitaxy with extremely low V/III ratios using tertiarybutylphosphine

Abstract: Metalorganic vapor phase epitaxy of InP with extremely low V/III ratios less than 10 was successfully carried out by using tertiarybutylphosphine, and detailed electrical and optical properties were investigated for the first time. Featureless surface morphology was obtained even with a V/III ratio of as low as 3. Good electrical properties, such as carrier concentrations of about 6×1014 cm−3 and electron Hall mobilities more than 30 000 cm2/V s measured at 77 K were confirmed, although both Van der Pauw and low‐temperature photoluminescence results proved the increased acceptor concentrations in the low V/III ratio range.

Measurement of Electromagnetic Parameters of Metal-Coating Thickness Measures

Abstract: Thickness measures for electrically conductive coatings applied to electrically conductive bases are described, for which not only geometrical but also electrophysical parameters such as the specific electrical conductivity and complex relative permeability of the measure base and the specific electrical conductivity of the measure coating are prescribed. The procedure and a technique for measuring the specific electrical conductivity of the base of a measure using the van der Pauw method, the complex relative magnetic permeability of metal on ring-shaped samples using a permeameter, a technique for transferring the value of this parameter to the measure base of an arbitrary shape with a flat surface, and also the procedure and a method for measuring the specific electrical conductivity of the coating-measure material with the use of an eddy current probe with a wave-like drive winding are described.

Design and fabrication of a simple four point probe system for electrical characterization of thin films

Abstract: The electrical characteristics of semiconductor thin films are of great practical interest in microelectronics industry hence the need to measure these parameters in a cheaper and faster manner possible. This study has embarked on design and fabrication of a simple, effective and portable computer-aided four point probe system for thin film sheet resistivity measurement. A four point probe head has been designed and fabricated from easily available materials. A relay switching device has also been designed and fabricated to perform switching of the probe tips on the sample surface as per the Van der Pauw set up. A Keithley SourceMeter 2400 model has been interfaced to a LabVIEW running computer via the serial port (RS-232 port) for its full control by the computer. The relay switching device has also been interfaced to the computer via the printer port (LPT1 port). The fabricated probe head, the relay switching device and Keithley SourceMeter were used to probe the samples as per the Van der Pauw set up with a square symmetry adopted for sheet resistivity measurement. To test the workability and reliability of the fabricated system for thin film sheet resistivity measurement, the sheet resistivity of Cu₂O semiconductor thin films prepared by DC reactive magnetron sputtering technique were measured. The sheet resistivity measured at room temperature of 23°C was found to be 55.65 Ω cm. However, as the samples were exposed to temperature rise, the sheet resistivity was found to decrease and was at its minimum value of 29.67 Ω cm at 170°C. Cu₂O thin films prepared at different sputtering pressures were also electrically characterized using the system. The sheet resistivity of the thin films were found to increase with increase in sputtering pressure. Films deposited at sputtering pressure of 1.8x10¯² mbar had sheet resistivity of 33.63 Ω cm and this increased to 62.23 Ω cm for films prepared at higher sputtering pressure of 2.4x10¯² mbar. From the measurements obtained, it was found from the study that the system offers a reliable, effective and simple technique for thin film sheet resistivity measurements.