Crystallinity improvement of ZnO nanorods by optimization of low-cost electrodeposition technique

• n-Type ZnO nanorods were electrochemically deposited employing standard DC power supply and milliammeter.
• ZnO nanorods show very good polycrystalline and electrical properties consistent with the literature.
• ZnO nanorod structures are hexagonal wurtzite and highly oriented along the c-axis perpendicular to the substrates.
• Produced ZnO nanorod structures show good transparent conductive oxide properties.

Extremely low-cost electrodeposition technique was developed to deposit ZnO nanorods. The growth process was performed using standard DC power supply, milliammeter and two-electrode electrochemical cell. The deposition was carried out on indium tin oxide (ITO) coated glass substrates by changing deposition parameters such as cathodic deposition current and time, solution molarity and temperature. The parameters varied to obtain optimum transparent semiconductor material for optoelectronic applications. Structural characterizations by X-ray diffraction (XRD) indicate the formation of polycrystalline phase ZnO with strong c-axis orientation and were sensitive to deposition temperatures and molarity as well. Average optical transmittance for the best two ZnO nanorod series was around 60% and 42%, respectively. The optical energy band gap of the ZnO nanorods decreased from 3.24 eV to 3.21 eV as the deposition time increased. All the nanorods were n-type with a high carrier concentration of 1 × 1020 cm− 3 and low 1–2 × 10− 3 Ωcm resistivity.