Dielectric properties and study of AC electrical conduction mechanisms by non-overlapping small polaron tunneling model in Bis(4-acetylanilinium) tetrachlorocuprate(II) compound

Studies on the Impedance Characteristics, Dielectric Relaxation, and ac Conductivity in Silicon Oxycarbide (SiOxCy:H) Films at the Amorphous-to-Nanocrystalline Transition Zone

“…Many frameworks can be intended to link the ac conduction mechanism with the s(T) behavior in finding the most likely conduction mechanism for the sample's ac conductivity. The following theoretical frameworks are most relevant according to the existing literature: 29,63 I. The nonoverlapping small polaron tunneling (NSPT) model, wherein the frequency exponent (s) grows as temperature increases.…”

“…Charge carriers or small polarons may be trapped at structural defects or localized states, resulting in ac conductivity due to the tunneling of such trapped charge carriers or small polarons. The frequency exponent (s), as indicated by the NSPT model, can be written as 63,64 ( )…”

“…Many frameworks can be intended to link the ac conduction mechanism with the s ( T ) behavior in finding the most likely conduction mechanism for the sample’s ac conductivity. The following theoretical frameworks are most relevant according to the existing literature: , The nonoverlapping small polaron tunneling (NSPT) model, wherein the frequency exponent ( s ) grows as temperature increases. The correlated barrier hopping model, wherein s declines as temperature increases. The overlapping large polaron tunneling model, wherein s is temperature- and frequency-dependent. On increasing the temperature, it reduces to a lower limit before growing as the temperature increases further. The quantum mechanical tunneling model, wherein s is ∼0.8 and it grows marginally with temperature or remains temperature-independent. …”

“…Charge carriers or small polarons may be trapped at structural defects or localized states, resulting in ac conductivity due to the tunneling of such trapped charge carriers or small polarons. The frequency exponent ( s ), as indicated by the NSPT model, can be written as , in this equation, τ 0 is the typical relaxation time (∼10 –13 s, nearly the atomic vibrational period), W H denotes the activation energy for small polaron transfer, K B is the Boltzmann constant, and T is the absolute temperature.…”

Complex Dielectric Characteristics, ac-Conductivity, and Impedance Spectroscopy of B-Doped nc-SiOX:H Thin Films

“…Actually, the term “small” implies that the polarons are localized with their distortion clouds non-overlapping . According to the small polaron tunneling model, n can be expressed by where ω is the frequency in Hz (s –1 ), T is the temperature in K, τ 0 is the characteristic relaxation time (∼10 –13 s, in the order of atomic vibrational period), K B is the Boltzmann constant, and W H is the polaron hopping energy (height of the maximum barrier). , Using this model, the polaron hopping energy ( W H ) has been calculated and the corresponding magnitudes are ∼0.23 and 0.45 eV for nc-SiO X :H (sample A) and a-SiO X :H (sample B) thin films prepared at CO 2 = 0.25 sccm and CO 2 = 0.40 sccm, respectively.…”