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The fabrication of white light-emitting diodes using the n-ZnO/NiO/p-GaN heterojunction with enhanced luminescence
Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
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2013 (English)In: Nanoscale Research Letters, ISSN 1931-7573, E-ISSN 1556-276X, Vol. 8, no 320Article in journal (Refereed) Published
Abstract [en]

Cheap and efficient white light-emitting diodes (LEDs) are of great interest due to the energy crisis all over the world. Herein, we have developed heterojunction LEDs based on the well-aligned ZnO nanorods and nanotubes on the p-type GaN with the insertion of the NiO buffer layer that showed enhancement in the light emission. Scanning electron microscopy have well demonstrated the arrays of the ZnO nanorods and the proper etching into the nanotubes. X-ray diffraction study describes the wurtzite crystal structure array of ZnO nanorods with the involvement of GaN at the (002) peak. The cathodoluminescence spectra represent strong and broad visible emission peaks compared to the UV emission and a weak peak at 425 nm which is originated from GaN. Electroluminescence study has shown highly improved luminescence response for the LEDs fabricated with NiO buffer layer compared to that without NiO layer. Introducing a sandwich-thin layer of NiO between the n-type ZnO and the p-type GaN will possibly block the injection of electrons from the ZnO to the GaN. Moreover, the presence of NiO buffer layer might create the confinement effect.

Place, publisher, year, edition, pages
2013. Vol. 8, no 320
Keyword [en]
White light-emitting diode; ZnO nanorods; Nanotubes; NiO buffer layer
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:liu:diva-103341DOI: 10.1186/1556-276X-8-320ISI: 000331642900001OAI: oai:DiVA.org:liu-103341DiVA: diva2:688549
Available from: 2014-01-17 Created: 2014-01-17 Last updated: 2017-12-06Bibliographically approved
In thesis
1. The synthesis, characterization and device fabrication of ZnO, NiO and their composite nanostructures
Open this publication in new window or tab >>The synthesis, characterization and device fabrication of ZnO, NiO and their composite nanostructures
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Electronics industry has been revolutionized since last few decades because of the fabrication of electronic devices by using nanoscale based materials. But the more innovative feature in the electronic devices is the use of transparent materials, which makes the transparent electronic devices as one of the most interesting research field in nanoscience and nano-technology now a days. In order to have high performance electronic devices based on the wide band gap compound semiconductors, a selection of right transparent material is crucial step. Among all the transparent metal oxides, ZnO is one of the potential candidates due to the ease in the synthesis process, wide bandgap of 3.37 eV, a high exciton binding energy of 60 meV and diverse morphologies. Since p-type ZnO based nanodevices are still difficult to fabricate due to the instability and unreliability of p-type ZnO nanomaterial, therefore several p-type semiconductors are used for the development of p-n junctions. Among those NiO is suitable p-type compound semiconductor to make p-n junction with ZnO because of its wide band gap of 3.7 eV and environment friendly conditions for its synthesis. Keeping these attractive properties of n-type ZnO and p-type NiO, the synthesis of composite nanostructures of these two transparent oxides and fabrication of their electronic devices is presented in this dissertation work.

I started my work with the synthesis of ZnO nanostructures focusing on the effect of different anions of zinc salts on the morphology and crystallinity of ZnO nanostructures. Then I grow honey-comb like NiO nanostructures on 3D nickel foam and used these nanostructures for the detection of Zinc ion. After that synthesized NiO and ZnO based composite nanostructures and characterized them, having main focus on the luminescence properties of ZnO when decorated with NiO nanostructures. The composite nanostructures of p-type NiO and n-type ZnO showed enhancement in the luminescence properties. Since pn junction is the back bone of electronic devices so working on the designing of band alignment along with the current transport properties of p-type NiO/n-type ZnO composite structures, an attempt was put forwarded to explain the phenomenon of these compound semiconducting materials. Different devices based on these two compound semiconducting materials are fabricated and designed in the present dissertation work, however still more work is required to improve the efficiency of devices like LEDs and UV detectors.

Place, publisher, year, edition, pages
Linköping: Linköping University Electronic Press, 2014. 55 p.
Series
Linköping Studies in Science and Technology. Dissertations, ISSN 0345-7524 ; 1562
Keyword
Zinc oxide; Nickel Oxide; Composite nanostructures; Wide band gap; Low temperature growth; Luminescence, Photo-detector; Light emitting diode
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-103343 (URN)
Public defence
2014-01-24, Kåkenhus, Campus Norrköping, Linköpings universitet, Norrköping, 10:00 (English)
Opponent
Supervisors
Available from: 2014-01-17 Created: 2014-01-17 Last updated: 2014-09-18Bibliographically approved

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