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Electroluminescence of ordered ZnO nanorod array/p-GaN light-emitting diodes with graphene current spreading layer.

Dong JJ, Hao HY, Xing J, Fan ZJ, Zhang ZL - Nanoscale Res Lett (2014)

Bottom Line: Ordered ZnO nanorod array/p-GaN heterojunction light-emitting diodes (LEDs) have been fabricated by introducing graphene as the current spreading layer, which exhibit improved electroluminescence performance by comparison to the LED using a conventional structure (indium-tin-oxide as the current spreading layer).In addition, by adjusting the diameter of ZnO nanorod array in use, the light emission of the ZnO nanorod array/p-GaN heterojunction LEDs was enhanced further.This work has great potential applications in solid-state lighting, high performance optoelectronic devices, and so on. 78.60.Fi; 85.60.Jb; 78.67.Lt; 81.10.Dn.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Science, China University of Geosciences (Beijing), 29 Xue Yuan Road, Haidian District, Beijing, 100083, China.

ABSTRACT

Unlabelled: Ordered ZnO nanorod array/p-GaN heterojunction light-emitting diodes (LEDs) have been fabricated by introducing graphene as the current spreading layer, which exhibit improved electroluminescence performance by comparison to the LED using a conventional structure (indium-tin-oxide as the current spreading layer). In addition, by adjusting the diameter of ZnO nanorod array in use, the light emission of the ZnO nanorod array/p-GaN heterojunction LEDs was enhanced further. This work has great potential applications in solid-state lighting, high performance optoelectronic devices, and so on.

Pacs: 78.60.Fi; 85.60.Jb; 78.67.Lt; 81.10.Dn.

No MeSH data available.


EL spectra of the ZnO nanorod array/p-GaN LEDs. With (a) graphene as the current spreading layer and (b) traditional structure, under various currents ranging from 2 to 10 mA. The insets show the schematic structures of the corresponding LEDs, respectively.
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Figure 3: EL spectra of the ZnO nanorod array/p-GaN LEDs. With (a) graphene as the current spreading layer and (b) traditional structure, under various currents ranging from 2 to 10 mA. The insets show the schematic structures of the corresponding LEDs, respectively.

Mentions: The EL spectra of ordered ZnO nanorod array/p-GaN LED (the diameter of the ZnO nanorods in use is 300 nm) with graphene current spreading layer under various currents ranging from 2 to 10 mA are shown in Figure 3a. It can be seen that these spectra exhibit a distinct UV emission peak centered at about 390 nm, which has been observed frequently from the EL spectra of ZnO-based LEDs and can be attributed to the near-band edge (NBE) emission from ZnO [13-15]. Besides, the strong EL emission even at low currents can be attributed to the low density of the interfacial defects, the improved carrier injection efficiency through the nanosized junctions [16,17], and the increase in the light extraction efficiency by virtue of the waveguiding property of ZnO nanorods [6,15]. For comparison, a reference LED with a traditional structure (containing a PMMA insulating layer and a top ITO current spreading layer) was fabricated, and the corresponding EL spectra and its schematic structure are presented in Figure 3b. Obviously, the EL emission from the ZnO nanorod array-based LED with graphene current spreading layer is stronger than that of the traditional structure at all injection currents, which can be due to the stable, reliable, and low-resistance ohmic contacts between graphene and ZnO nanorods, as well as the higher transmittance of graphene than ITO especially in the UV region [8].


Electroluminescence of ordered ZnO nanorod array/p-GaN light-emitting diodes with graphene current spreading layer.

Dong JJ, Hao HY, Xing J, Fan ZJ, Zhang ZL - Nanoscale Res Lett (2014)

EL spectra of the ZnO nanorod array/p-GaN LEDs. With (a) graphene as the current spreading layer and (b) traditional structure, under various currents ranging from 2 to 10 mA. The insets show the schematic structures of the corresponding LEDs, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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Figure 3: EL spectra of the ZnO nanorod array/p-GaN LEDs. With (a) graphene as the current spreading layer and (b) traditional structure, under various currents ranging from 2 to 10 mA. The insets show the schematic structures of the corresponding LEDs, respectively.
Mentions: The EL spectra of ordered ZnO nanorod array/p-GaN LED (the diameter of the ZnO nanorods in use is 300 nm) with graphene current spreading layer under various currents ranging from 2 to 10 mA are shown in Figure 3a. It can be seen that these spectra exhibit a distinct UV emission peak centered at about 390 nm, which has been observed frequently from the EL spectra of ZnO-based LEDs and can be attributed to the near-band edge (NBE) emission from ZnO [13-15]. Besides, the strong EL emission even at low currents can be attributed to the low density of the interfacial defects, the improved carrier injection efficiency through the nanosized junctions [16,17], and the increase in the light extraction efficiency by virtue of the waveguiding property of ZnO nanorods [6,15]. For comparison, a reference LED with a traditional structure (containing a PMMA insulating layer and a top ITO current spreading layer) was fabricated, and the corresponding EL spectra and its schematic structure are presented in Figure 3b. Obviously, the EL emission from the ZnO nanorod array-based LED with graphene current spreading layer is stronger than that of the traditional structure at all injection currents, which can be due to the stable, reliable, and low-resistance ohmic contacts between graphene and ZnO nanorods, as well as the higher transmittance of graphene than ITO especially in the UV region [8].

Bottom Line: Ordered ZnO nanorod array/p-GaN heterojunction light-emitting diodes (LEDs) have been fabricated by introducing graphene as the current spreading layer, which exhibit improved electroluminescence performance by comparison to the LED using a conventional structure (indium-tin-oxide as the current spreading layer).In addition, by adjusting the diameter of ZnO nanorod array in use, the light emission of the ZnO nanorod array/p-GaN heterojunction LEDs was enhanced further.This work has great potential applications in solid-state lighting, high performance optoelectronic devices, and so on. 78.60.Fi; 85.60.Jb; 78.67.Lt; 81.10.Dn.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Science, China University of Geosciences (Beijing), 29 Xue Yuan Road, Haidian District, Beijing, 100083, China.

ABSTRACT

Unlabelled: Ordered ZnO nanorod array/p-GaN heterojunction light-emitting diodes (LEDs) have been fabricated by introducing graphene as the current spreading layer, which exhibit improved electroluminescence performance by comparison to the LED using a conventional structure (indium-tin-oxide as the current spreading layer). In addition, by adjusting the diameter of ZnO nanorod array in use, the light emission of the ZnO nanorod array/p-GaN heterojunction LEDs was enhanced further. This work has great potential applications in solid-state lighting, high performance optoelectronic devices, and so on.

Pacs: 78.60.Fi; 85.60.Jb; 78.67.Lt; 81.10.Dn.

No MeSH data available.