Photocurrent detection of chemically tuned hierarchical ZnO nanostructures grown on seed layers formed by atomic layer deposition
Open Access
- 6 June 2012
- journal article
- Published by Springer Science and Business Media LLC in Nanoscale Research Letters
- Vol. 7 (1), 290
- https://doi.org/10.1186/1556-276x-7-290
Abstract
We demonstrate the morphological control method of ZnO nanostructures by atomic layer deposition (ALD) on an Al2O3/ZnO seed layer surface and the application of a hierarchical ZnO nanostructure for a photodetector. Two layers of ZnO and Al2O3 prepared using ALD with different pH values in solution coexisted on the alloy film surface, leading to deactivation of the surface hydroxyl groups. This surface complex decreased the ZnO nucleation on the seed layer surface, and thereby effectively screened the inherent surface polarity of ZnO. As a result, a 2-D zinc hydroxyl compound nanosheet was produced. With increasing ALD cycles of ZnO in the seed layer, the nanostructure morphology changes from 2-D nanosheet to 1-D nanorod due to the recovery of the natural crystallinity and polarity of ZnO. The thin ALD ZnO seed layer conformally covers the complex nanosheet structure to produce a nanorod, then a 3-D, hierarchical ZnO nanostructure was synthesized using a combined hydrothermal and ALD method. During the deposition of the ALD ZnO seed layer, the zinc hydroxyl compound nanosheets underwent a self-annealing process at 150 °C, resulting in structural transformation to pure ZnO 3-D nanosheets without collapse of the intrinsic morphology. The investigation on band electronic properties of ZnO 2-D nanosheet and 3-D hierarchical structure revealed noticeable variations depending on the richness of Zn-OH in each morphology. The improved visible and ultraviolet photocurrent characteristics of a photodetector with the active region using 3-D hierarchical structure against those of 2-D nanosheet structure were achieved.Keywords
This publication has 37 references indexed in Scilit:
- Biomimetic syntheses of pure or doped metal hydroxide nitrate thin films by a dual-template approachJournal of Materials Chemistry, 2009
- Hydrothermal growth of ZnO nanostructuresScience and Technology of Advanced Materials, 2009
- Impact of interfacial polymer morphology on photoexcitation dynamics and device performance in P3HT/ZnO heterojunctionsJournal of Materials Chemistry, 2009
- Novel rose-like ZnO nanoflowers synthesized by chemical vapor depositionMaterials Letters, 2008
- Novel hydrogen gas sensor based on single ZnO nanorodMicroelectronic Engineering, 2008
- Fine Tuning of the Face Orientation of ZnO Crystals to Optimize Their Photocatalytic ActivityAdvanced Materials, 2006
- A comprehensive review of ZnO materials and devicesJournal of Applied Physics, 2005
- Catalyst-free large-quantity synthesis of ZnO nanorods by a vapor–solid growth mechanism: Structural and optical propertiesJournal of Crystal Growth, 2005
- ZnO Nanobridges and NanonailsNano Letters, 2002
- Studies on a potentiometric urea biosensor based on an ammonia electrode and urease, immobilized on a γ-aluminum oxide matrixAnalytica Chimica Acta, 1997