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Superionic conducting nanomaterials; AgI-CuI solid solutions; electronic conductivity; structural phase transitions

A study of electronic conductivity using the DC polarization technique has been carried out for AgI and Ag_1−xCu_xI (where x=0.05, 0.15, 0.25) solid solutions over a range of temperatures from 300 K to 473 K. A diode-like current-voltage characteristics arises from microscopic p-n junctions an enhanced electronic conductivity of the order of 10⁻³A is observed for undoped AgI and Cu-doped AgI. Activation energies (E_a) for electronic conductivity obtained from log σ (Ω⁻¹ cm⁻¹) vs. 1000/T (K⁻¹) were 0.48, 0.6, 0.74 and 1.01 eV for AgI, Ag_0.95Cu_0.05I, Ag_0.85Cu_0.15I and Ag_0.75Cu_0.25I solid solutions respectively. The near-twofold increase in activation energy (1.01 eV) observed upon 25% Cu doping is due to the substantial concentration of current carriers/holes injected by Cu while replacing Ag⁺ in AgI.

D Bharathi Mohan¹ C S Sunandana¹

1. School of Physics, University of Hyderabad, Hyderabad - 500 046, India

Published

August 2006

Manuscript received

3 January 2006

Manuscript revised

21 April 2006

Accepted

1 June 2006