Non-contact detection of a naturally formed oxide layer on copper metal surface using terahertz time-domain spectroscopy

Cafe, Arven; Reyes, Alexander Delos; Lopez, Lorenzo; Husay, Horace Andrew; Faustino, Maria Angela; Mag-usara, Valynn Katrine; Tani, Masahiko; Salvador, Arnel; Somintac, Armando; Estacio, Elmer

doi:10.1016/j.cap.2023.03.007

Cited by 2 publications

(1 citation statement)

References 35 publications

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“…As for other non-contact measurement methods like terahertz time-domain spectroscopy, electrical resistivity is measured based on the light excitation of the electronic response inside different energy bands and mainly focused on semiconductors [ 17 , 18 , 19 , 20 , 21 ]. The strong absorption of several metal materials in the spectrum, such as Cu, would greatly increase the difficulty of result analysis [ 22 ]. Contact measurement can be conducted using two-probe, three-probe, four-probe, and van der Pauw methods.…”

Section: Introductionmentioning

confidence: 99%

Electrical Resistivity Measurements of Surface-Coated Copper Foils

Ni,

Yan,

Liu

et al. 2024

Materials

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Due to the direct contact between the probe and sample, the contact of the four-probe method is important for the structural integrity of the sample and the accuracy of electrical resistivity measurements, especially for surface-coated metal foils with multilayered structures. Here, we analyzed the accuracy and stability of four-probe method probing on different sides of copper (Cu) foils covered with graphene (Gr). Theoretical simulations showed similar potential distributions on the probe tip when probing on the Cu and Gr sides. The resistivity of the Gr/Cu foil was 2.31 ± 0.02 μΩ·cm when measured by probing on the Cu side, and 2.30 ± 0.10 μΩ·cm when measured by probing on the Gr side. The major difference in the mean deviation is attributed to surface damage. In addition, the method of probing on the Cu side was sensitive to the resistivity changes of Gr induced by polymers with a dielectric constant range of 2~12, which is consistent with the calculations based on the random phase approximation theory. Our results demonstrated that the probing position on the metal side in the four-probe method can effectively protect the structural integrity of the functional surface-coated layer and maintain the high sensitivity of the measurement, providing guidance for the resistivity measurements of other similarly heterogeneous materials.

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Section: Introductionmentioning

confidence: 99%

Electrical Resistivity Measurements of Surface-Coated Copper Foils

Ni,

Yan,

Liu

et al. 2024

Materials

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Tellurium Photonic Crystal-Based Terahertz Polarization Splitter Using a Diamond-Shaped Ferrite Pillar Array

Zhang,

Zeng,

Wang

2024

Crystals

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A T-shaped photonic crystal waveguide was designed with square lattice tellurium photonic crystals. A diamond-shaped ferrite pillar array was inserted in the junction of the waveguide to make a novel terahertz polarization splitter. Both transverse electric and transverse magnetic modes were numerically investigated by the plane wave expansion method, which used complete photonic band gaps covering from 0.138 THz to 0.144 THz. In this frequency domain of the fully polarized band gaps, the transmission efficiency of the photonic crystal waveguide was up to −0.21 dB and −1.67 dB for the transverse electric and transverse magnetic modes, respectively. Under the action of a DC magnetic field, the THz waves were rotated 90 degrees by the diamond-shaped ferrite pillar array. Transverse electric waves or transverse magnetic waves can be separated by a polarization isolator (six smaller tellurium rods) from the fixed waves. The characteristics of the designed polarization splitter were analyzed by the finite element method, and its transmission efficiency was optimized to 95 percent by fine-tuning the radii of the thirteen ferrite pillars. A future integrated communication network of sky–earth–space will require fully polarized devices in the millimeter and terahertz wavebands. The envisaged polarization splitter has a unique function and provides a promising method for the realization of fully polarized 6G devices.

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Non-contact detection of a naturally formed oxide layer on copper metal surface using terahertz time-domain spectroscopy

Cited by 2 publications

References 35 publications

Electrical Resistivity Measurements of Surface-Coated Copper Foils

Electrical Resistivity Measurements of Surface-Coated Copper Foils

Tellurium Photonic Crystal-Based Terahertz Polarization Splitter Using a Diamond-Shaped Ferrite Pillar Array

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