Effect of boron doping on the structural, optical and electrical properties of ZnO nanoparticles produced by the hydrothermal method

Abstract

Abstract The effect of boron doping with 0–11 at% concentration on structural, optical and electrical properties of zinc oxide nanopowder synthesized by a hydrothermal method has been reported. We have performed X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), optical, Hall and resistivity measurements on the samples. XRD results reveal that all B doped ZnO nanopowders have single phase hexagonal (Wurtzite) structure without any impurity. But the positions of main diffracted peaks of ZnO shifted slightly towards small (2 θ ) angle and grain size decreases from 60.75 nm to 34.34 nm with an increase of B doping concentrations. SEM analysis indicates that the doping concentration of B affected the surface morphology of ZnO nanostructures. Optical properties were examined by UV–vis absorption/diffuse reflectance spectroscopy. The optical band gap of Zn 1− x B x O nanostructures increased from 3.27 eV to 3.30 eV with increasing doping from x =0 to x =0.11. The role of doping concentrations of B on the transport properties was searched by temperature dependent Hall measurements in 180–350 K temperature range. The carrier concentration of the samples increased from 0.11×10 14 cm −3 to 4.08×10 14 cm −3 , the Hall mobility decreased from 5.61 cm 2 V −1 s −1 to 1.22 cm 2 V −1 s −1 and electrical resistivity decreased from 10.89×10 4 Ω cm to 1.25×10 4 Ω cm with the increase of the B doping concentrations at room temperature. The electrical resistivity is observed to decrease with both the increase in dopant concentration and the temperature in the range of 180–350 K.