Elsevier, Materials Science and Engineering: B, 2(166), p. 147-151
DOI: 10.1016/j.mseb.2009.10.030
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The temperature dependent transport properties of molybdenum oxide (MoO3) doped N,N′-di(1-naphthyl)-N,N′-diphenylbenzidin (α-NPD) were studied over a frequency range of 100Hz to 1MHz. The value of trap density and mobility calculated by detailed analysis of current–voltage (I–V) characteristics are 9.43×1026m−3 and 1.23×10−6cm2V−1s−1, respectively. The relaxation time for the carriers in the bulk and in the interface region decreases with temperature. The Cole–Cole plot indicates the device can be modeled as the combination of two parallel resistor–capacitor (R–C) circuits with a series resistance of around 70Ω. The dc conductivity shows two different regions in the studied temperature range with activation energy of Ea∼0.107eV (region I) and Ea∼52meV (region II), respectively. The ac conductivity follows the universal power law and the onset frequency increases with increase of temperature. The temperature dependent conduction mechanism can be explained by correlated hopping barrier (CBH) model.