Improvement of electroluminescence performance by integration of ZnO nanowires and single-crystalline films on ZnO/GaN heterojunction

Shi, Zhifeng; Zhang, Yuantao; Cui, Xiao‐Bing; Wu, Bin; Zhuang, Shiwei; Yang, Xiaotian; Zhang, Baolin; Du, Guotong

doi:10.1063/1.4870517

Cited by 26 publications

(20 citation statements)

References 17 publications

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“…Due to the advanced physical and chemical properties, the integration of ZnO nanostructures (nanowires or quantum dots) with GaN could be a feasible approach to obtain light-emitting diodes (LEDs) with high performance. 13,15,19,20 Several kinds of low-dimensional nanostructures have been studied extensively. However, it is known that the optoelectronic properties of these devices are greatly influenced by the surface properties of ZnO nanostructures.…”

Section: Introductionmentioning

confidence: 99%

Ultraviolet Electroluminescence from ZnS@ZnO Core–Shell Nanowires/p-GaN Introduced by Exciton Localization

Fang

Wei

Yang

et al. 2016

ACS Appl. Mater. Interfaces

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We investigate the electroluminescence (EL) from light emitting diodes (LEDs) of ZnO nanowires/p-GaN structure and ZnS@ZnO core-shell nanowires/p-GaN structure. With the increase of forward bias, the emission peak of ZnO nanowires/p-GaN structure heterojunction shows a blue-shift, while the ZnS@ZnO core-shell nanowires/p-GaN structure demonstrates a changing EL emission; the ultraviolet (UV) emission at 378 nm can be observed. This discrepancy is related to the localized states introduced by ZnS particles, which results in a different carrier recombination process near the interfaces of the heterojunction. The localized states capture the carriers in ZnO nanowires and convert them to localized excitons under high forward bias. A strong UV emission due to localized excitons can be observed. Our results indicated that utilizing localized excitons should be a new route toward ZnO-based ultraviolet LEDs with high efficiency.

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Section: Introductionmentioning

confidence: 99%

Ultraviolet Electroluminescence from ZnS@ZnO Core–Shell Nanowires/p-GaN Introduced by Exciton Localization

Fang

Wei

Yang

et al. 2016

ACS Appl. Mater. Interfaces

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“…The efficiency of the carrier injection was enhanced in nanosized junctions between the n-type ZnO nanorod and the p-type GaN substrate. Shi et al reported on ZnO nanowire-based LEDs prepared by MOCVD on p-type GaN substrates with efficient electroluminescence and rectifying behavior with the turn-on voltage of 3.7 V [13]. The electroluminescence was attributed to near-band-edge emission in ZnO and acceptor-to-band transition in GaN depending on the region of charge carrier recombination.…”

Section: Introductionmentioning

confidence: 99%

Highly Rectifying Heterojunctions Formed by Annealed ZnO Nanorods on GaN Substrates

et al. 2020

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We study the effect of thermal annealing on the electrical properties of the nanoscale p-n heterojunctions based on single n-type ZnO nanorods on p-type GaN substrates. The ZnO nanorods are prepared by chemical bath deposition on both plain GaN substrates and on the substrates locally patterned by focused ion beam lithography. Electrical properties of single nanorod heterojunctions are measured with a nanoprobe in the vacuum chamber of a scanning electron microscope. The focused ion beam lithography provides a uniform nucleation of ZnO, which results in a uniform growth of ZnO nanorods. The specific configuration of the interface between the ZnO nanorods and GaN substrate created by the focused ion beam suppresses the surface leakage current and improves the current-voltage characteristics. Further improvement of the electrical characteristics is achieved by annealing of the structures in nitrogen, which limits the defect-mediated leakage current and increases the carrier injection efficiency.

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“…[22] However, due to the lack of a method of synthesizing reproducible and stable p-type ZnO, an alternative procedure is employed to synthesize n-type ZnO NRs on a p-type substrate e.g., GaN to achieve ZnO NRs-based heterojunction LEDs. [80][81][82][83][84][85][86][87] However, the LEDs based on this configuration usually show low EL response as a result of high density of defects and different energy barriers for electrons and holes at the heterojunction interface. [87] It is known that the interface defect states can act as non-radiative centers that will drastically diminish the efficiency of ZnO-based heterojunction LEDs.…”

Section: Influence Of the Zno Seed Layer Precursor Molar Ratios On Thmentioning

confidence: 99%

“…[80][81][82][83][84][85][86][87] However, the LEDs based on this configuration usually show low EL response as a result of high density of defects and different energy barriers for electrons and holes at the heterojunction interface. [87] It is known that the interface defect states can act as non-radiative centers that will drastically diminish the efficiency of ZnO-based heterojunction LEDs. [85,86] Previously, it has been indicated that the type of the seed layer utilized in the synthesis of the ZnO NRs can significantly modify the density of such interface defects, and so different color emissions can be observed.…”

Section: Influence Of the Zno Seed Layer Precursor Molar Ratios On Thmentioning

confidence: 99%

“…As can be observed, the EL spectra of all the three devices show a distinct yellow emission peak centered at ~575 nm, which can be ascribed to intrinsic DL defects emission in ZnO due to point defects e.g., VO and Oi or be interpreted by the interface defects related emission. [82][83][84][85][88][89][90][91] In addition to the yellow emission, a weak blue emission centered at ~ 420 nm was observed for device 1 (with a 1:1 M seed layer) as presented in Figure 5.4 (a). This observation can be attributed to the transitions from the CB or shallow donors (in ZnO) to the Mg acceptor levels in the p-GaN.…”

Section: Influence Of the Zno Seed Layer Precursor Molar Ratios On Thmentioning

confidence: 99%

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Toward the Optimization of Low-temperature Solution-based Synthesis of ZnO Nanostructures for Device Applications

Alnoor¹

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One-dimensional (1D) nanostructures (NSs) of Zinc Oxide (ZnO) such as nanorods (NRs) have recently attracted considerable research attention due to their potential for the development of optoelectronic devices such as ultraviolet (UV) photodetectors and light-emitting diodes (LEDs). The potential of ZnO NRs in all these applications, however, would require synthesis of high crystal quality ZnO NRs with precise control over the optical and electronic properties. It is known that the optical and electronic properties of ZnO NRs are mostly influenced by the presence of native (intrinsic) and impurities (extrinsic) defects. Therefore, understanding the nature of these intrinsic and extrinsic defects and their spatial distribution is critical for optimizing the optical and electronic properties of ZnO NRs. However, identifying the origin of such defects is a complicated matter, especially for NSs, where the information on anisotropy is usually lost due to the lack of coherent orientation. Thus, the aim of this thesis is towards the optimization of the lowtemperature solution-based synthesis of ZnO NRs for device applications. In this connection, we first started with investigating the effect of the precursor solution stirring durations on the deep level defects concentration and their spatial distribution along the ZnO NRs. Then, by choosing the optimal stirring time, we studied the influence of ZnO seeding layer precursor’s types, and its molar ratios on the density of interface defects. The findings of these investigations were used to demonstrate ZnO NRs-based heterojunction LEDs. The ability to tune the point defects along the NRs enabled us further to incorporate cobalt (Co) ions into the ZnO NRs crystal lattice, where these ions could occupy the vacancies or interstitial defects through substitutional or interstitial doping. Following this, high crystal quality vertically welloriented ZnO NRs have been demonstrated by incorporating a small amount of Co into the ZnO crystal lattice. Finally, the influence of Co ions incorporation on the reduction of core-defects (CDs) in ZnO NRs was systematically examined using electron paramagnetic resonance (EPR)

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Improvement of electroluminescence performance by integration of ZnO nanowires and single-crystalline films on ZnO/GaN heterojunction

Cited by 26 publications

References 17 publications

Ultraviolet Electroluminescence from ZnS@ZnO Core–Shell Nanowires/p-GaN Introduced by Exciton Localization

Ultraviolet Electroluminescence from ZnS@ZnO Core–Shell Nanowires/p-GaN Introduced by Exciton Localization

Highly Rectifying Heterojunctions Formed by Annealed ZnO Nanorods on GaN Substrates

Toward the Optimization of Low-temperature Solution-based Synthesis of ZnO Nanostructures for Device Applications

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