Efficient charge-transport UV sensor based on interlinked ZnO tetrapod networks

• Published in: Surface & coatings technology Vol. 306; pp. 25 - 29
• Main Authors: Thepnurat, Meechai, Ruankham, Pipat, Phadunghitidhada, Surachet, Gardchareon, Atcharawon, Wongratanaphisan, Duangmanee, Choopun, Supab
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.11.2016
• Subjects: Charge transport; Electrodes; Grain boundaries; Interlinked ZnO tetrapod networks (ITN-ZnO); Microwave-assisted thermal oxidation; Nanostructure; Networks; Optoelectronic devices; Potential barriers; Sensors; UV sensor; Zinc oxide; Zinc oxide (ZnO); Interlinked ZnO tetrapod networks (ITN-ZnO); Charge transport; Zinc oxide (ZnO); UV sensor; Microwave-assisted thermal oxidation
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2016.04.005

UV sensors based on inter-linked ZnO tetrapod networks (ITN-ZnO) were fabricated, characterized and compared with ones based on ZnO tetrapods (T-ZnO) and ZnO powders (P-ZnO) in terms of morphology-related charge dynamics. Photoluminescence measurement showed that the ITN-ZnO had the highest order of crystallinity among these nanostructures. Moreover, impedance spectroscopy analysis revealed that potential barrier at the grain boundary of ITN-ZnO was relatively lower that of T-ZnO and P-ZnO. This was because the coulombic leg-to-leg linking of ITN-ZnO as confirmed by electron microscope observation. The lower potential barriers significantly promoted transport of UV-generated charge carriers that were required to reach Au electrodes, leading to lower sensor resistance. Based on the achieved results, charge transport mechanisms were also proposed. These sensor characteristics suggested that the ITN-ZnO was greatly applicable for UV sensors and other optoelectronic devices. •UV sensor based on ITN-ZnO with efficient charge-transport is demonstrated.•ITN-ZnO sensor shows superior UV response and differs from tetrapod and powder.•Superior UV response can explain by reduction of potential barrier at grain boundary.•ITN-ZnO is applicable for efficient UV sensor and other optoelectronic devices.