Controlled growth of c-axis oriented ZnO nanorod array films by electrodeposition method and characterization

• ZnO nanorod array films were deposited on p-Si by electrochemical deposition method.
• p-Si/ZnO was characterized by different electrochemical methods.
• p-Si/ZnO can be suggested as an electrode material for supercapacitor applications.

ZnO nanorod array films were deposited from aqueous solution containing different concentrations (1 × 10−2 M and 5 × 10−3 M) Zn(NO3)2⋅6H2O and C6H12N4 and at different electrodeposition times (i.e., 15 min, 30 min, 60 min, 120 min and 180 min) using chronoamperometry method on p-Si substrate. Surface morphology and crystal structural properties of ZnO films were investigated by XRD and FESEM to select ZnO films which have optimum properties. The highest TC(h k l) value was observed in (0 0 2) plane for the film, which is deposited at 1 × 10−2 M and 120 min. It is also observed that the highly oriented nanorods in this film are denser. Additionally, the conductivity type was determined by using Mott–Schottky which is electrochemical impedance spectroscopy method (EIS). On the other hand, to investigate the utility of obtained ZnO on p-Si (p-Si/n-ZnO) as supercapacitor electrode active material, the electrochemical storage properties of p-Si/ZnO was studied by electrochemical impedance spectroscopy and repeating chronopotentiometry methods. It is suggested from electrochemical tests results that p-Si/ZnO is a promising electrode materials for supercapacitor applications that required low voltage (<10 V). Rectifiying behavior was observed from the I–V characteristic of nanorod array n-ZnO/p-Si heterojunction diode. The n value, Io and the ϕb were found to be 5.48, 1.93 × 10−8 A and 0.75 eV, respectively.

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