Investigating the temperature and frequency dependence of dielectric response using AC impedance spectroscopy on SnO2

Abstract

In this investigation, we explored tin oxide's dielectric properties and impedance spectroscopy, focusing on its temperature dependence across a frequency range of 20 Hz to 2 MHz. We analyzed the x-ray diffraction pattern using Rietveld refinement and established that the sample has a tetragonal phase with P42/mnm space group. Afterward, the surface structure of the SnO2 was examined using (FESEM) and Raman spectroscopy. Through FESEM, we analyzed the morphology of the prepared sample, which were nanospheres in structure. In contrast, we discovered the non-degenerated A1g and B2g modes through Raman spectroscopy, which matches well with the literature and displays the contraction and expansion of Sn-O bonds. We performed dielectric studies at varying frequencies and temperatures to further analyze the properties. We discovered that the ac conductivity increased as temperature and frequency increased. The activation energy was calculated using dc electrical conductivity measurement. The DC conductivity exhibits a temperature dependence that can be described by the Arrhenius equation, which reveals that the tin oxide has to conduct behavior with an estimated activation energy of 0.025 eV, 0.035 eV, and 0.082 eV for three temperature ranges of 80–120 K, 120–175 K, and 175–270 K, respectively. Additionally, the AC conductivity data conforms to Jonscher's universal power law. The frequency-dependent parameter “s” increases as the temperature elevates. A transition from the QMT (Quantum mechanical tunneling) model to NSPT (non-overlapping small polaron tunneling) was employed to analyze the data.