Localized Charge Carrier Transport Properties of Zn1-x Ni (x) O/NiO Two-Phase Composites

Joshi, DC and Dasari, K and Nayak, S and Palai, R and Suresh, P and Thota, S (2016) Localized Charge Carrier Transport Properties of Zn1-x Ni (x) O/NiO Two-Phase Composites. In: JOURNAL OF ELECTRONIC MATERIALS, 45 (4). pp. 2059-2065.

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Abstract

We report the localized charge carrier transport of two-phase composite Zn1-x Ni (x) O/NiO (0 a parts per thousand currency sign x a parts per thousand currency sign 1) using the temperature dependence of ac-resistivity rho (ac)(T) across the N,el temperature T (N) (= 523 K) of nickel oxide. Our results provide strong evidence to the variable range hopping of charge carriers between the localized states through a mechanism involving spin-dependent activation energies. The temperature variation of carrier hopping energy epsilon (h)(T) and nearest-neighbor exchange-coupling parameter J (ij)(T) evaluated from the small poleron model exhibits a well-defined anomaly across T (N). For all the composite systems, the average exchange-coupling parameter (J (ij))(AVG) nearly equals to 70 meV which is slightly greater than the 60-meV exciton binding energy of pure zinc oxide. The magnitudes of epsilon (h) (similar to 0.17 eV) and J (ij) (similar to 11 meV) of pure NiO synthesized under oxygen-rich conditions are consistent with the previously reported theoretical estimation based on Green's function analysis. A systematic correlation between the oxygen stoichiometry and, epsilon (h)(T) and J (ij)(T) is discussed.

Item Type:	Journal Article
Publication:	JOURNAL OF ELECTRONIC MATERIALS
Publisher:	SPRINGER
Additional Information:	Copy right for this article belongs to the SPRINGER, 233 SPRING ST, NEW YORK, NY 10013 USA
Keywords:	Variable range hopping; sol-gel process; activation energy; exchange-coupling parameter
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	23 Apr 2016 05:22
Last Modified:	23 Apr 2016 05:22
URI:	http://eprints.iisc.ac.in/id/eprint/53680

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