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Investigation into the impedance, dielectric behavior, and conductivity within p-silicon/n-nanocrystalline iron disilicide heterojunctions and equivalent circuit model in relation to temperature
Author(s)
Borwornpornmetee, Nattakorn
Sittimart, Phongsaphak
Traiprom, Thawichai
Paosawatyanyong, Boonchoat
Yoshitake, Tsuyoshi
Date Issued
March 15, 2025
Type
Article
Abstract
The p-Si/n-nanocrystalline FeSi2 heterojunctions constructed through facing-targets sputtering were characterized for impedance under various frequencies and temperatures of between 160−400 K. Imaginary and real impedance plots for all temperatures demonstrated single semicircular arc with negative temperature dependency. From the arc, a circuit model equivalent to electrode resistance serially connected to several loops, each consisting of a parallel circuit comprising a resistance//constant phase element (Q), corresponding to the crystallite, crystallite boundary, and interface. All resistances increased with decreasing temperatures, while the Q values decreased but behaved as ideal capacitors for all temperatures. The dielectric constants versus increasing temperature demonstrated a linear increase. At 300 K and 1 MHz, the dielectric constant was 24.5 with 0.1 loss tangent, denoting its possible usage for filtration and storage. The alternating-current conductivities disclosed that direct-current conductivities increased as the temperature increased. The exponents from Jonscher's fit were 1 or less around 180 K and the values beyond 1 at higher temperatures, indicating the shift from long transitional transport to localized hopping transport. The activation energy based on conductivities was higher than the one based on relaxation times, implying that excess charge led to more energy requirements for transportation.
Citation
Materials Science in Semiconductor Processing, 188, 2025