Augmented Photoelectrochemical Efficiency of ZnO/TiO2 Nanotube Heterostructures

• Published in: Journal of electronic materials Vol. 46; no. 11; pp. 6698 - 6703
• Main Authors: Boda, Muzaffar Ahmad, Shah, Mohammad Ashraf
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-11-2017; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Charge transfer; Chemistry and Materials Science; Diffuse reflectance spectroscopy; Electromagnetic absorption; Electron mobility; Electronics and Microelectronics; Heterostructures; Instrumentation; Light diffraction; Materials Science; Microcrystals; Nanotubes; Optical and Electronic Materials; Photoelectric effect; Photoelectric emission; Photovoltaic cells; Scanning electron microscopy; Solid State Physics; Titanium dioxide; Titanium oxides; Ultraviolet spectroscopy; X-ray diffraction; Zinc oxide; electron mobility; Nanotube heterostructures; photocurrent; band bending
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-017-5710-7

ZnO/TiO
2
nanotube heterostructures have been fabricated by electrodeposition of ZnO microcrystals over electrochemically anodized TiO
2
nanotube arrays. The resulting ZnO/TiO
2
nanotube heterostructures showed enhanced photocurrent density of 5.72 mA cm
−2
, about 1.5 times the value of 3.68 mA cm
−2
shown by bare compact TiO
2
nanotubes. This enhanced photocurrent density of the ZnO/TiO
2
nanotube heterostructures is due to high electron mobility in the ZnO crystals, thereby decreasing the electron–hole recombination process, good interfacial quality between the ZnO and TiO
2
structures, and a proposed smooth charge-transfer mechanism due to band bending at the interface. The morphological features of the as-prepared heterostructures were determined by field-emission scanning electron microscopy (FESEM). The crystallinity and phase purity of the samples were confirmed by x-ray diffraction (XRD) analysis. The light absorption properties of the prepared samples were investigated by ultraviolet–visible diffuse reflectance spectroscopy (UV–Vis DRS). The photoelectrochemical efficiency of bare and ZnO-modified TiO
2
nanotube heterostructures was determined by electrochemical analyzer.