Hydrothermal synthesis of ZnO thin films and its electrical characterization

We herein report the synthesis of ZnO thin films on a pre-treated p-type silicon substrate by hydrothermal method and its electrical characterization. The as-synthesized nanostructures were characterized by field emission scanning electron microscopy, X-ray diffraction and current-voltage measurements. The presence of citric acid (CA) in the solution resulted in a morphological change from well-aligned nanorods to relatively smooth, compact thin films. As the concentration of the citric acid increased from 1 mM to 5 mM, the thickness of the films decreased from 1.3 μm to 320 nm. All the as-grown nanostructures are crystalline and are preferentially oriented along the c-axis. Finally, the typical current-voltage measurements indicated that the thin films have better rectification with lower leakage currents.