No abstract

This paper focused on developing a methodology and metrology using a differential photoacoustic (PA) system to determine the effective water vapor diffusion coefficient [Formula: see text] and the effective permeability coefficient [Formula: see text] in thin films as a piece of paper and standard polystyrene for a controlled relative humidity. The methodology proposes a new differential photoacoustic system, including the water reservoir, relative humidity, and temperature detectors. Two cells, reference/sample, were used to obtain the instrumental function to reduce the electronic and environmental noises. A method based on the study of [Formula: see text] and the behaviors of R2 as a function of the number of data was proposed to assess the region in which the photoacoustic signal should be processed to determine each effective coefficient. S is the amplitude of the PA signal, [Formula: see text] is the initial amplitude value, [Formula: see text] is the change, t (time), and [Formula: see text] is the water vapor diffusion time. The effective water diffusion coefficient [Formula: see text] for water and polystyrene was 1.90 × 10−11 m2/s and 3.09 × 10−11 m2/s, respectively. The permeability coefficient value for the piece of paper was 4.18 × 10−9 mol kg−1 cm−2 s−1 Pa−1, while for polystyrene, it was 6.80 × 10−9 mol kg−1 cm−2 s−1 Pa−1 for 70% of relative humidity. This methodology can be extended by changing the moisture content on the chamber to obtain the dependence of [Formula: see text] as a function of relative humidity.

No abstract

In monocrystalline semiconductor materials, their structural properties govern thermal and electrical ones. Here, the effect of defects induced by intrinsic and extrinsic parameters on the structural, thermal, and electrical properties during manufacturing processes and samples preparation in p-type Si wafers with different carrier concentrations was investigated. Photocarrier images in a Si wafer 0.005 Ω·cm showed that Boron carrier distribution exhibit variation across wafer. The Hall effect measurements in cut and polished samples delivered structural damages affecting the carrier lifetime. The crystalline quality obtained by studying the FWHM of the X-Ray patterns elucidated the effect of intrinsic carrier contribution on the structural properties. Thermal diffusivity and heat capacity of the cut samples exhibit a decrease as carrier concentration increases being affected by the crystal damage. Thermal and electrical properties are governed by structure state determined by intrinsic and extrinsic parameters.