Niobium doping effect on electrical and optical properties of ZnO nanorods produced by ultrasonic spray pyrolysis

Abstract

Niobium metal doped ZnO nanorods were fabricated on a glass substrate using an ultrasonic spray pyrolysis system in two steps. The structural, morphological, and optical properties of the produced samples were investigated via an x-ray diffractometer (XRD), a field emission scanning electron microscopy (FE-SEM) combined with energy dispersive x-ray spectroscopy (EDX), and a spectrophotometer, respectively. The XRD patterns were indexed in the hexagonal (wurtzite) unit cell type for all the ZnO samples. In addition, according to the XRD peaks, the crystals grew in the c-axis (002) direction. The morphological features of the obtained thin films were examined. From the SEM micrographs, it was observed that ZnO thin films doped with Nb had a nanorod structure in the c-axis direction. The presence of Nb ions in the samples was proved via EDX analysis. The electrical conductivity values of the pristine and 10 % mol Nb-doped ZnO samples were 3.16 x 10−9 and 3.98 x 10−7 (ohm−1.cm−1) at 25 °C; and 7.08 x 10−7 and 5.01 x 10−5 (ohm−1.cm−1) at 300 °C, respectively. The optical transmittances of the samples were measured at wavelengths of 350–1000 nm. It was observed that the produced films had high optical transparency. The average optical transmittance value of the samples was 90 %.