Influence of copper contact thickness on Cu/ZnO nanorods-enhanced Schottky diode

In this report, ZnO nanorods (NRs) were synthesized on ITO glass substrate with the help of ZnO seed layer by chemical bath deposition technique. Cu metal contacts were then deposited on top of the ZnO NRs by magnetron sputtering through masking to form a Schottky diode. The morphological, structural, and optical characteristics of the grown ZnO NRs were studied. The effect of different thickness of Cu metal contacts on its electrical properties was also investigated. X-ray diffraction spectra showed that the ZnO NRs exhibit hexagonal wurtzite structure with (002) orientation. Field emission scanning electron microscope (FESEM) images showed that the ZnO NRs were vertically aligned and well orientated. The absorption spectra of ZnO NRs indicates that it has transparency over the visible light region which is in agreement to the literatures. It was found out that the optical bandgap is 3.26 eV which is slightly lower than bulk ZnO. The I–V measurement were conducted for different Cu metal thickness and the electronic parameters such as ideality factor and Schottky barrier height were calculated for each sample. The obtained results show that the effect of metal thickness on the electrical properties of ZnO and the possibility of tuning Schottky barrier height by varying the metal contact thickness.