| 1. |
- Khun, Kimleang, et al.
(författare)
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Comparative study of ZnO nanorods and thin films for chemical and biosensing applications and the development of ZnO nanorods based potentiometric strontium ion sensor
- 2013
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Ingår i: Applied Surface Science. - : Elsevier. - 0169-4332 .- 1873-5584. ; 268, s. 37-43
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the comparative study of ZnO nanorods and ZnO thin films were performed regarding the chemical and biosensing properties and also ZnO nanorods based strontium ion sensor is proposed. ZnO nanorods were grown on gold coated glass substrates by the hydrothermal growth method and the ZnO thin films were deposited by electro deposition technique. ZnO nanorods and thin films were characterised by field emission electron microscopy [FESEM] and X-ray diffraction [XRD] techniques and this study has shown that the grown nanostructures are highly dense, uniform and exhibited good crystal quality. Moreover, transmission electron microscopy [TEM] was used to investigate the quality of ZnO thin film and we observed that ZnO thin film was comprised of nano clusters. ZnO nanorods and thin films were functionalised with selective strontium ionophore salicylaldehyde thiosemicarbazone [ST] membrane, galactose oxidase, and lactate oxidase for the detection of strontium ion, galactose and l-lactic acid, respectively. The electrochemical response of both ZnO nanorods and thin films sensor devices was measured by using the potentiometric method. The strontium ion sensor has exhibited good characteristics with a sensitivity of 28.65 +/- 0.52 mV/decade, for a wide range of concentrations from 1.00 x 10(-6) to 5.00 x 10(-2) M, selectivity, reproducibility, stability and fast response time of 10.00 s. The proposed strontium ion sensor was used as indicator electrode in the potentiometric titration of strontium ion versus ethylenediamine tetra acetic acid [EDTA]. This comparative study has shown that ZnO nanorods possessed better performance with high sensitivity and low limit of detection due to high surface area to volume ratio as compared to the flat surface of ZnO thin films.
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| 2. |
- Semchuk, O. Yu, et al.
(författare)
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Laser ablation lithography on thermoelectric semconductor
- 2006
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 252:13, s. 4759-4762
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, experimental results of the investigation of the periodic structure on thermoelectric semiconductor Cu2Se are presented. Periodic structures were formed on surfaces of semiconductors due to multi-beam interaction of Q-switched Nd:YAG laser, which was operated in the lowest order of Gaussian mode and pulse duration 7 ns. Surface temperature evolution and transient reflectivity are studied during laser treatment. Creation of Cu islands in the maximal intensity of interference pattern was found.
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| 3. |
- Yang, L.L., et al.
(författare)
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A SIMS study on Mg diffusion in Zn(0.94)Mg(0.06)O/ZnO heterostructures grown by metal organic chemical vapor deposition
- 2011
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Ingår i: Applied Surface Science. - : Elsevier Science B.V., Amsterdam.. - 0169-4332 .- 1873-5584. ; 257:20, s. 8629-8633
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Tidskriftsartikel (refereegranskat)abstract
- Zn(0.94)Mg(0.06)O/ZnO heterostructures have been grown on 2 in. sapphire wafer using metal organic chemical vapor deposition (MOCVD). Photoluminescence (PL) mapping demonstrates that Mg distribution on the entire wafer is very uniform (standard deviation of Mg concentration/mean Mg concentration = 1.38%) with average concentration of similar to 6%. The effect of annealing on the Mg diffusion in Zn(0.94)Mg(0.06)O/ZnO heterostructures has been investigated in detail by using secondary ion mass spectrometry (SIMS). All the Mg SIMS depth profiles have been fitted by three Gaussian distribution functions. The Mg diffusion coefficient in the as-grown Zn(0.94)Mg(0.06)O layer deposited at 700 degrees C is two orders of magnitude lower than that of annealed samples, which clearly indicates that the deposition temperature of 700 degrees C is much more beneficial to grow ZnMgO/ZnO heterostructures and quantum wells.
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| 4. |
- Yang, Li-Li, et al.
(författare)
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Origin of the surface recombination centers in ZnO nanorods arrays by X-ray photoelectron spectroscopy
- 2010
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Ingår i: Applied Surface Science. - Amsterdam, Netherlands : Elsevier. - 0169-4332 .- 1873-5584. ; 256:11, s. 3592-3597
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Tidskriftsartikel (refereegranskat)abstract
- The surface composition of as-grown and annealed ZnO nanorods arrays (ZNAs) grown by a two-step chemical bath deposition method has been investigated by X-ray photoelectron spectroscopy (XPS). XPS confirms the presence of OH bonds and specific chemisorbed oxygen on the surface of ZNAs, as well as H bonds on (1 0 (1) over bar 0) surfaces which has been first time observed in the XPS spectra. The experimental results indicated that the OH and H bonds play the dominant role in facilitating surface recombination but specific chemisorbed oxygen also likely affect the surface recombination. Annealing can largely remove the OH and H bonds and transform the composition of the other chemisorbed oxygen at the surface to more closely resemble that of high temperature grown ZNAs, all of which suppresses surface recombination according to time-resolved photoluminescence measurements.
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