Ac conductivity of transition metal oxide doped glassy nanocomposite systems: temperature and frequency dependency

作者：Das Anindya Sundar; Roy Madhab; Biswas Dipankar; Kundu Ranadip; Acharya Amartya; Roy Debasish; Bhattacharya Sanjib^*

来源：Materials Research Express, 2018, 5(9): 095201.

DOI：10.1088/2053-1591/aad43e

• ac conductivity and Jonscher's power law
• crossover frequency and power law exponent
• non-overlapping small polaron tunneling (NSPT) and correlated barrier hopping (CBH) models
• mobile charge carrier concentration
• almond-west formalism

Transition metal oxide (TMO) doped different types of semiconducting glassy systems of the common terminology as 0.3V(2)O(5)-0.7 (0.05A(m)O(n)-0.95ZnO) for A(m)O(n). =. MoO3, SeO2, Nd2O3, and CdO have been prepared by melt quenching route. The frequency and temperature dependent conductivity of all the as-quenched glass nanocomposite samples has been investigated over a wide temperature and frequency range. Conductivity, depending on temperature and frequency, is well established using Jonscher's universal power law and Almond-West formalism. The values ofDCconductivity (sigma(dc)), polaron hopping frequency (omega(H)), frequency exponent (n), and power law exponent (s) have been computed. The value of n indicates three-dimensional motions of charge carriers or polarons, which is the main reason for high-frequency dispersion in the ac conductivity. The estimated values of activation energy of ac conduction (E-ac), free energy of polaron migration (EH) and activation energy ofDCconductivity (E-dc) are mainly owing to polaron transport with the energy level in the optical band gap. Ac conductivity and temperature dependent power-law exponent (s) of the as-prepared glassy samples containingMoO(3) and Nd2O3 are dominated by non-overlapping small polaron tunneling (NSPT). Conversely, correlated barrier hopping (CBH) solely controls the ac conductivity and temperature dependent power-law exponent (s) of the glassy samples containing SeO2 and CdO. It is ascertained that mobile charge carrier concentration is independent of temperature and only 20%-25% of the total charge carriers (polarons) contribute to the ac conductivity of the presently studied glassy systems.

• 出版日期2018-9