Synthesis and characterization of undoped and copper-doped zinc oxide nanowires for optoelectronic and solar cells applications

This work concentrated on the synthesis of undoped and Cu-doped ZnO nanowires (NWs) by vapor transport method as well as on their physical and chemical characterizations. All X-ray diffraction patterns were indexed to ZnO single phase of hexagonal structure, and no Cu or Cu compounds characteristic peaks were observed. The evaluated Cu at.% was proportional with Cu ratios used in the source alloys. NWs morphology with quite long and smooth surfaces was observed for undoped sample, whereas NWs with agglomerations of particles were observed for higher Cu-doped samples. The overall transmittance decreased with increasing Cu doping ratio with a red shift for the onset of absorption. The optical energy gap was decreased from 3.33 to 3.10 eV upon increasing the Cu ratio from 0 to 5 at.%. Two emission bands were observed in the photoluminescent spectra at 385 and 545 nm, and they were strongly tailored via Cu doping. All the samples exhibited semiconducting behavior with two activation energies. The sensitivity to the NO2 gas was increased with Cu doping ratio. The magnetization measurements revealed ferromagnetic behavior for all the NWs samples at room temperature.

Automated summary

This study focused on the synthesis and characterizations of undoped and Cu-doped ZnO nanowires (NWs) using the vapor transport method. The results showed that Cu doping affected the morphology and optical properties of the NWs, increased sensitivity to NO2 gas, and induced ferromagnetic behavior at room temperature.