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.

Experiments and simulation on diffusion and activation of codoped with arsenic and phosphorous germanium

Abstract: We report arsenic and phosphorus diffusion experiments and activation related phenomena in codoped germanium substrates utilizing conventional thermal annealing. Chemical profiles were obtained by secondary ion mass spectroscopy, sheet resistance was estimated by the Van der Pauw method. Our study covers the temperature range from 600 to 750 °C. We accurately described the dopant profiles with a quadratic dependence of the dopants diffusion coefficient on the free electron concentration. In our simulations we considered the dopant pile-up near the surface and dopant loss owing to outdiffusion during the annealing. Although the double donor codoping technique exhibited no advantage over monodoping with P concerning the level of activation and junction depth, it was interesting to observe the different diffusion behavior of the two dopants. Whereas the diffusion of As indicates a retardation under codoping the diffusion of P remains either unaffected or is slightly enhanced by codoping. The activation level of the codoped samples remains lower compared to the respective monodoped samples, except for the highest annealing temperature.

Oxide Thin Film Diode Fabricated by Liquid-Phase Method

Abstract: A p-type oxide thin film, NiO, and an n-type thin film, ZnO, were fabricated by a liquid phase method using metal acetates as starting reagents. Both the films were transparent, uniform in thickness and porous. By repetition of coating of the n- and p-type films a p–n contact was formed. The contact exhibited nonlinear and rectifying I–V characteristics. A Mott-Schottky plot of the p–n contact revealed that the carrier concentration in each film was constant throughout the thickness and the carrier concentration in NiO was much lower than that estimated from the results obtained using the van der Pauw method. The very low carrier concentration may be due to the existence of interface and surface states in the multilayered porous film.

Layered GaTe Crystals for Radiation Detectors

Abstract: In this work we investigated a new method of growing detector grade large GaTe layered chalcogenide single crystals. GaTe ingots (2" diameter) were grown by a novel method using graphite crucible by slow crystallization from a melt of high purity (7 N) Ga and zone refined (ZR) Te precursors in an argon atmosphere. GaTe samples from the monocrystalline area of the ingot have been cleaved mechanically and characterized using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive analysis by x-rays (EDX), atomic force microscopy (AFM), x-ray photoelectron spectroscopy (XPS), transfer length method (TLM), resistivity measurements using van der Pauw technique, Hall effect, and capacitance-voltage (C-V) measurements. Our investigations reveal a novel method of growing superior quality GaTe crystals for large volume inexpensive nuclear radiation detectors.

Cadmium telluride films on foreign substrates

Abstract: Thin films of cadmium telluride have been deposited on mullite and tungsten‐coated graphite substrates at 500–700 °C by the direct combination of cadmium and tellurium in a hydrogen atmosphere Their microstructure and crystallographic properties were studied The importance of controlling the Cd/Te molar ratio in the reaction mixture to obtain nearly stoichiometric films was demonstrated The electrical properties of nonstoichiometric and nearly stoichiometric films on mullite substrates were measured by the van der Pauw technique Schottky barriers were used to measure the electrical properties of cadmium telluride films on W/graphite substrates The effective intragrain minority carrier diffusion length in n‐type films was measured by the scanned electron beam method using a Schottky barrier structure