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Ahmed N, Khalil Z, Farooq Z, Khizar-ul-Haq, Shahida S, Ramiza, Ahmad P, Qadir KW, Khan R, Zafar Q. Structural, Optical, and Magnetic Properties of Pure and Ni-Fe-Codoped Zinc Oxide Nanoparticles Synthesized by a Sol-Gel Autocombustion Method. ACS OMEGA 2024; 9:137-145. [PMID: 38239284 PMCID: PMC10796112 DOI: 10.1021/acsomega.3c01727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 10/09/2023] [Indexed: 01/22/2024]
Abstract
Pure and Ni-Fe-codoped Zn1 - 2xNixFexO (x = 0.01, 0.02, 0.03, and 0.04) nanoparticles were effectively synthesized using a sol-gel autocombustion procedure. The structural, optical, morphological, and magnetic properties were determined by using X-ray diffraction (XRD), ultraviolet-visible (UV-vis), scanning electron microscopy, and vibrating sample magnetometer techniques. The XRD confirmed the purity of the hexagonal wurtzite crystal structure. XRD analysis further indicated that Fe and Ni successfully substituted the lattice site of Zn and generated a single-phase Zn1-2xNixFexO magnetic oxide. In addition, a significant morphological change was observed with an increase in the dopant concentration by using high-resolution scanning electron microscopy. The UV-vis spectroscopy analysis indicated the redshift in the optical band gap with increasing dopant concentration signifying a progressive decrease in the optical band gap. The vibrating sample magnetometer analysis revealed that the doped samples exhibited ferromagnetic properties at room temperature with an increase in the dopant concentration. Dopant concentration was confirmed by using energy-dispersive X-ray spectroscopy. The current results provide a vital method to improve the magnetic properties of ZnO nanoparticles, which may get significant attention from researchers in the field of magnetic semiconductors.
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Affiliation(s)
- Nasar Ahmed
- Department
of Physics, King Abdullah Campus, University
of Azad Jammu and Kashmir, Muzaffarabad 13100, Pakistan
| | - Zakia Khalil
- Department
of Physics, Mirpur University of Science
and Technology, Muzaffarabad, Azad Jammu and Kashmir 10250, Pakistan
| | - Zahid Farooq
- Department
of Physics, Division of Science and Technology, University of Education, Lahore 54000, Pakistan
| | - Khizar-ul-Haq
- Department
of Physics, Mirpur University of Science
and Technology, Muzaffarabad, Azad Jammu and Kashmir 10250, Pakistan
| | - Shabnam Shahida
- Department
of Chemistry, University of Poonch, Rawalakot, Azad Kashmir 12350, Pakistan
| | - Ramiza
- Department
of Physics, University of Agriculture, Faisalabad 38000, Pakistan
| | - Pervaiz Ahmad
- Department
of Physics, King Abdullah Campus, University
of Azad Jammu and Kashmir, Muzaffarabad 13100, Pakistan
| | - Karwan Wasman Qadir
- Computation
Nanotechnology Research Lab (CNRL), Department of Physics, College
of Education, Salahaddin University-Erbil, Erbil, Kurdistan 44002, Iraq
- Renewable
Energy Technology Department, Erbil Technology College, Erbil Polytechnic University, Erbil, Kurdistan 44001, Iraq
| | - Rajwali Khan
- Department
of Physics, University of Lakki Marwat, Lakki Marwat, Khyber Pakhtunkhwa 28440, Pakistan
- Department
of Physics, United Arab Emirates University, Al ain 15551, United Arab Emirates
| | - Qayyum Zafar
- Department
of Physics, University of Management and
Technology, Lahore 54000, Pakistan
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2
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O’Boyle SK, Fagan AM, Steimle BC, Schaak RE. Expanded Tunability of Intraparticle Frameworks in Spherical Heterostructured Nanoparticles through Substoichiometric Partial Cation Exchange. ACS MATERIALS AU 2022; 2:690-698. [PMID: 36397875 PMCID: PMC9661727 DOI: 10.1021/acsmaterialsau.2c00038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
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Partial cation exchange
reactions provide a synthetic pathway for
rationally constructing heterostructured nanoparticles that incorporate
different materials at precise locations. Multiple sequential partial
cation exchange reactions can produce libraries of exceptionally complex
heterostructured nanoparticles, but the first partial exchange reaction
is responsible for defining the intraparticle frameworks that persist
throughout and help to direct subsequent exchanges. Here, we studied
the partial cation exchange behavior of spherical nanoparticles of
roxbyite copper sulfide, Cu1.8S, with substoichiometric
amounts of Zn2+. We observed the formation of ZnS–Cu1.8S–ZnS sandwich spheres, which are already well known
in this system, as well as ZnS–Cu1.8S Janus spheres
and Cu1.8S–ZnS–Cu1.8S central
band spheres, which have not been observed previously as significant
subpopulations of samples. Aliquots taken during the formation of
the heterostructured nanoparticles suggest that substoichiometric
amounts of Zn2+ limit the number of sites per particle
where exchange initiates and/or propagates, thereby helping to define
intraparticle frameworks that are different from those observed using
excess amounts of exchanging cations. We applied these insights from
mixed-population samples to the higher-yield synthesis of ZnS–Cu1.8S Janus spheres, as well as the higher-order derivatives
ZnS–(CdS–Cu1.8S), ZnS–(CdS–ZnS),
and ZnS–(CdS–CoS), which have unique features relative
to previously reported analogues. These results demonstrate how the
diversity of intraparticle frameworks in spherical nanoparticles can
be expanded to produce a broader range of downstream heterostructured
products.
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Wang R, Xu C, You D, Wang X, Chen J, Shi Z, Cui Q, Qiu T. Plasmon-exciton coupling dynamics and plasmonic lasing in a core-shell nanocavity. NANOSCALE 2021; 13:6780-6785. [PMID: 33885480 DOI: 10.1039/d0nr08969a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Plasmonic nanolasers based on the spatial localization of surface plasmons (SPs) have attracted considerable interest in nanophotonics, particularly in the desired application of optoelectronic and photonic integration, even breaking the diffraction limit. Effectively confining the mode field is still a basic, critical and challenging approach to improve optical gain and reduce loss for achieving high performance of a nanolaser. Here, we designed and fabricated a semiconductor/metal (ZnO/Al) core-shell nanocavity without an insulator spacer by simple magnetron sputtering. Both theoretical and experimental investigations presented plasmonic lasing behavior and SP-exciton coupling dynamics. The simulation demonstrated the three-dimensional optical confinement of the light field in the core-shell nanocavity, while the experiments revealed a lower threshold of the optimized ZnO/Al core-shell nanolaser than the same-sized ZnO photonic nanolaser. More importantly, the blue shift of the lasing mode demonstrated the SP-exciton coupling in the ZnO/Al core-shell nanolaser, which was also confirmed by low-temperature photoluminescence (PL) spectra. The analysis of the Purcell factor and PL decay time revealed that SP-exciton coupling accelerated the exciton recombination rate and enhanced the conversion of spontaneous radiation into stimulated radiation. The results indicate an approach to design a real nanolaser for promising applications.
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Affiliation(s)
- Ru Wang
- State Key Laboratory of Bioelectronics, School of physics, Southeast University, Nanjing 210096, P. R. China.
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Lee Y, Kim SY, Kim DY, Lee S. Highly Sensitive UV Photodiode Composed of β-Polyfluorene/YZnO Nanorod Organic-Inorganic Hybrid Heterostructure. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1486. [PMID: 32751143 PMCID: PMC7466385 DOI: 10.3390/nano10081486] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 07/22/2020] [Accepted: 07/25/2020] [Indexed: 01/23/2023]
Abstract
The highly sensitive ultra-violet (UV) photodiode was demonstrated on the organic-inorganic hybrid heterostructure of β-phase p-type polyfluorene (PFO)/n-type yttrium-doped zinc oxide nanorods (YZO-NRs). The device was fabricated through a simple fabrication technique of β-phase PFO coating onto YZO-NRs that had been directly grown on graphene by the hydrothermal synthesis method. Under UV illumination (λ = 365 nm), the device clearly showed excellent photoresponse characteristics (e.g., high quantum efficiency ~690%, high photodetectivity ~3.34 × 1012 cm·Hz1/2·W-1, and fast response time ~0.17 s). Furthermore, the ratio of the photo current-to-dark current exceeds 103 even under UV illumination with a small optical power density of 0.6 mW/cm2. We attribute such superb photoresponse characteristics to both Y incorporation into YZO-NRs and conformation of β-phase PFO. Namely, Y dopants could effectively reduce surface states at YZO-NRs, and β-phase PFO might increase the photocarrier conductivity in PFO. The results suggest that the β-phase p-PFO/n-YZO-NR hybrid heterostructure holds promise for high-performance UV photodetectors.
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Affiliation(s)
- Youngmin Lee
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04623, Korea; (Y.L.); (D.Y.K.)
| | - Soo Youn Kim
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04623, Korea;
| | - Deuk Young Kim
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04623, Korea; (Y.L.); (D.Y.K.)
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04623, Korea;
| | - Sejoon Lee
- Quantum-Functional Semiconductor Research Center, Dongguk University-Seoul, Seoul 04623, Korea; (Y.L.); (D.Y.K.)
- Division of Physics & Semiconductor Science, Dongguk University-Seoul, Seoul 04623, Korea;
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5
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Why do nanowires grow with their c-axis vertically-aligned in the absence of epitaxy? Sci Rep 2020; 10:6554. [PMID: 32300133 PMCID: PMC7162979 DOI: 10.1038/s41598-020-63500-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 04/01/2020] [Indexed: 01/12/2023] Open
Abstract
Images of uniform and upright nanowires are fascinating, but often, they are quite puzzling, when the substrate is clearly not an epitaxial template. Here, we reveal the physics underlying one such hidden growth guidance mechanism through a specific example - the case of ZnO nanowires grown on silicon oxide. We show how electric fields exerted by the insulating substrate may be manipulated through the surface charge to define the orientation and polarity of the nanowires. Surface charge is ubiquitous on the surfaces of semiconductors and insulators, and as a result, substrate electric fields need always be considered. Our results suggest a new concept, according to which the growth of wurtzite semiconductors may often be described as a process of electric-charge-induced self-assembly, wherein the internal built-in field in the polar material tends to align in parallel to an external field exerted by the substrate to minimize the interfacial energy of the system.
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6
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Fiedler S, Lem LOLC, Ton-That C, Schleuning M, Hoffmann A, Phillips MR. Correlative Study of Enhanced Excitonic Emission in ZnO Coated with Al Nanoparticles using Electron and Laser Excitation. Sci Rep 2020; 10:2553. [PMID: 32054905 PMCID: PMC7018697 DOI: 10.1038/s41598-020-59326-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 01/13/2020] [Indexed: 11/24/2022] Open
Abstract
Recently, metal nanoparticle surface coatings have been found to significantly enhance the ultra-violet luminescence intensity from ZnO, providing a viable means to mitigate optical losses and improve LED performance. Although there is general agreement that resonantly excited Localized Surface Plasmons (LSPs) in metal nanoparticles can directly couple to excitons in the semiconductor increasing their spontaneous emission rate, the exact mechanisms involved in this phenomenon are currently not fully understood. In this work, LSP-exciton coupling in bulk and nanostructured ZnO coated with a 2 nm Al nanoparticle layer is investigated using correlative photoluminescence and depth-resolved cathodoluminescence and time-resolved photoluminescence spectroscopy. Temperature-resolved cathodoluminescence and photoluminescence measurements from 10 K to 250 K show free exciton (FX) emission enhancement factors up to 12x at 80 K, and reveal that the FX couple more efficiently to the LSPs compared to the localized donor-bound excitons. A strong polarization dependence between the LSPs and FX is observed where FX transitions are more strongly enhanced when polarized in the same direction as the electric field of the incident excitation, which is different for laser and electron beam sources. This result indicates that selective enhancement of the excitonic emission peaks in the ZnO coated with Al nanoparticles can be achieved by choosing the appropriate ZnO substrate orientation.
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Affiliation(s)
- Saskia Fiedler
- School of Mathematical and Physical Sciences, University of Technology Sydney, 15 Broadway, Ultimo, NSW, 2007, Australia. .,Centre for Nano Optics, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
| | - Laurent O Lee Cheong Lem
- School of Mathematical and Physical Sciences, University of Technology Sydney, 15 Broadway, Ultimo, NSW, 2007, Australia.,Australian National Fabrication Facility, Australian National University, Canberra, ACT 2601, Australia
| | - Cuong Ton-That
- School of Mathematical and Physical Sciences, University of Technology Sydney, 15 Broadway, Ultimo, NSW, 2007, Australia
| | - Markus Schleuning
- Technische Universität Berlin, Fakultät II, Institut für Festkörperphysik, Sekretariat EW 5-4, Hardenbergstr. 36, 10623, Berlin, Germany
| | - Axel Hoffmann
- Technische Universität Berlin, Fakultät II, Institut für Festkörperphysik, Sekretariat EW 5-4, Hardenbergstr. 36, 10623, Berlin, Germany
| | - Matthew R Phillips
- School of Mathematical and Physical Sciences, University of Technology Sydney, 15 Broadway, Ultimo, NSW, 2007, Australia.
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7
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Chan SY, Wu SC, Wang CY, Hsu HC. Enhanced ultraviolet electroluminescence from ZnO nanoparticles via decoration of partially oxidized Al layer. OPTICS EXPRESS 2020; 28:2799-2808. [PMID: 32121960 DOI: 10.1364/oe.382340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 01/10/2020] [Indexed: 06/10/2023]
Abstract
We construct the ZnO-based superluminescent light-emitting diodes (SLEDs) by spin-coating ZnO nano-particles onto p-GaN/sapphire substrate. By inserting another thin Al layer to form an n-ZnO/Al/n-ZnO/p-GaN sandwich structured SLD, the intensities of the photoluminescence and electroluminescence were greatly enhanced, which can be attributed to the surface plasmon resonance of this Al layer. The tendency of the intensities of the entire electroluminescence spectra shows a super-linearly behavior with increasing the forward bias. Besides, the spectral bandwidth is narrowed down enormously owing to the achievement of the SLD. Furthermore, the interfacial emissions between ZnO/GaN are effectively suppressed by partially oxidizing the Al layer.
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8
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Kwon OH, Jang JW, Park SJ, Kim JS, Hong SJ, Jung YS, Yang H, Kim YJ, Cho YS. Plasmonic-Enhanced Luminescence Characteristics of Microscale Phosphor Layers on a ZnO Nanorod-Arrayed Glass Substrate. ACS APPLIED MATERIALS & INTERFACES 2019; 11:1004-1012. [PMID: 30511826 DOI: 10.1021/acsami.8b13767] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present a planar luminescent layer for glare-free, long-lifespan white light-emitting diodes (LEDs), with attractive light outputs. The novel and facile remote phosphor approach proposed in this work enhances luminescence properties by combining a waveguiding ZnO-based nanostructure with plasmonic Au nanoparticles. The system comprised a microscale yellow phosphor layer that is applied by simple printing onto an Au nanoparticle-dispersed ZnO nanorod array. This architecture resulted in a considerable enhancement in luminous efficacy of approximately 18% because of the combination of waveguide effects from the nanorod structure and plasmonic effects from the Au nanoparticles. Performance was optimized according to the length of the Zn nanorods and the concentration of Au. An optimal efficiency of ∼84.26 lm/W for a silicate phosphor-converted LED was achieved using long ZnO nanorods and an Au concentration of 12.5 ppm. The finite-difference time-domain method was successfully used to verify the luminous efficacy improvements in the Au nanoparticle-intervened nanostructures via the waveguiding and plasmonic effects.
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Affiliation(s)
| | | | | | - Jun Sik Kim
- R&D Center , LG Display Co., Ltd , Paju-si , Gyeonggi-do 10843 , Korea
| | | | | | - Heesun Yang
- Department of Materials Science & Engineering , Hongik University , Seoul 04006 , Korea
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9
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One-Dimensional Zinc Oxide Nanomaterials for Application in High-Performance Advanced Optoelectronic Devices. CRYSTALS 2018. [DOI: 10.3390/cryst8050223] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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You D, Xu C, Qin F, Zhu Z, Manohari AG, Xu W, Zhao J, Liu W. Interface control for pure ultraviolet electroluminescence from nano-ZnO-based heterojunction devices. Sci Bull (Beijing) 2018; 63:38-45. [PMID: 36658916 DOI: 10.1016/j.scib.2017.12.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 11/14/2017] [Accepted: 11/28/2017] [Indexed: 01/21/2023]
Abstract
Realization of pure and stable ultraviolet electroluminescence (UV EL) of ZnO light-emitting diode (LED) is still a challenging issue, due to complicated defects of intrinsic ZnO and the corresponding device interfaces. In this paper, we demonstrated a simple & feasible method to fabricate n-ZnO/AlN/p-GaN heterojunctions light-emitting devices. First, the vertically aligned ZnO nanorods (NRs) have been prepared as high quality active layer, and the nanostructured heterojunction LED arrays were constructed by directly bonding ZnO NRs onto AlN-coated p-GaN wafer. By optimizing the AlN layer thickness to be 20 nm, a strong and pure ultraviolet emission located at 387 nm can be observed. The energy band alignment of n-ZnO/AlN (20 nm)/p-GaN heterojunction LED has been studied by using X-ray photoelectron spectroscopy (XPS), the valence band offset between AlN and GaN was calculated to be 0.34 eV. On the other side, the conduction band offset (as large as 3.28 eV) between AlN and ZnO can block the flow of electrons from ZnO to p-GaN. Thus, electron-hole recombination takes place in the ZnO layer, and a pure UV EL could be observed. Our results provide a significant approach toward future of pure ultraviolet optoelectronic LEDs.
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Affiliation(s)
- Daotong You
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China
| | - Chunxiang Xu
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China.
| | - Feifei Qin
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China
| | - Zhu Zhu
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China
| | - A Gowri Manohari
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China
| | - Wei Xu
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China
| | - Jie Zhao
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China
| | - Wei Liu
- State Key Laboratory of Bioelectronics, School of Biological Science & Medical Engineering, Southeast University, Nanjing 210096, China
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11
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Zhang C, Zhu F, Xu H, Liu W, Yang L, Wang Z, Ma J, Kang Z, Liu Y. Significant improvement of near-UV electroluminescence from ZnO quantum dot LEDs via coupling with carbon nanodot surface plasmons. NANOSCALE 2017; 9:14592-14601. [PMID: 28933500 DOI: 10.1039/c7nr04392a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Short-wavelength LEDs, a hot research topic in modern optoelectronics, have attracted tremendous attention in recent years because of their great application potential in both civil and military domains. Compared to conventional metallic surface-plasmons (SPs), carbon nanodot (CD) SPs with less optical loss and low cost, broader SP resonant frequency and good biocompatibility are expected to provide more prominent luminescence enhancement for light emitters. Herein, SP-enhanced near-UV emission quantum dot LEDs (Q-LED) were fabricated via introducing CDs into p-GaN/Al2O3/ZnO Q-LEDs by optimizing the molar ratio of ZnO quantum dots to CDs and a significant enhancement (∼20-fold) of the near-UV electroluminescence (EL) intensity from the ZnO-based Q-LEDs was achieved. Time-resolved spectroscopy studies reveal that the observed luminescence enhancement arises due to the resonant coupling between ZnO excitons and CD SPs. The current study not only demonstrates a feasible way to acquire near-UV emission from all-inorganic Q-LEDs, but also provides an effective strategy to enhance the EL intensity of these QD light emitters, which can further be extended to other types of light-emitting devices to improve EL efficiency.
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Affiliation(s)
- Cen Zhang
- Centre for Advanced Optoelectronic Functional Materials Research and Key Laboratory of UV-Emitting Materials and Technology (Northeast Normal University), Ministry of Education, Changchun 130024, China.
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12
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High-efficiency light emission by means of exciton–surface-plasmon coupling. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2017. [DOI: 10.1016/j.jphotochemrev.2017.05.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Bano N, Hussain I, Sawaf S, Alshammari A, Saleemi F. Enhancement of external quantum efficiency and quality of heterojunction white LEDs by varying the size of ZnO nanorods. NANOTECHNOLOGY 2017; 28:245203. [PMID: 28540864 DOI: 10.1088/1361-6528/aa6f7b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The size of ZnO nanorods (NRs) plays an important role in tuning the external quantum efficiency (EQE) and quality of light generated by white light emitting diodes (LEDs). In this work, we report on the enhancement of EQE and the quality of ZnO NR-based hetrojunction white LEDs fabricated on a p-GaN substrate using a low temperature solution method. Cathodoluminescence spectra demonstrate that ultraviolet (UV) emission decreases and visible deep band emission increases with an increase in the length of the ZnO NRs. The UV emission could be internally reabsorbed by the ZnO NR excitation, thus enhancing the emission intensity of the visible deep band. Photocurrent measurements validated the fact that the EQE depends on the size of ZnO NRs, increasing by 87% with an increase in the length of the ZnO NRs. Furthermore, the quality of white light was measured and clearly indicated an increase in the color rendering indices of the LEDs with an increase in the length of the ZnO NRs, confirming that the quality of light generated by LEDs can be tuned by varying the length of the ZnO NRs. These results suggest that the EQE and visible deep band emission from n-ZnONRs/p-GaN heterojunction LEDs can be effectively controlled by adjusting the length of the ZnO NRs, which can be useful for realizing tunable white LEDs.
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Affiliation(s)
- N Bano
- Department of Physics and Astronomy College of Science, King Saud University, Riyadh, Saudi Arabia
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14
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Ali A, Wang D, Wang J, Jiao S, Guo F, Zhang Y, Gao S, Ni S, Luan C, Wang D, Zhao L. ZnO nanorod arrays grown on an AlN buffer layer and their enhanced ultraviolet emission. CrystEngComm 2017. [DOI: 10.1039/c7ce00722a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ultraviolet luminescence of ZnO nanorods was greatly enhanced through introducing an AlN buffer layer.
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15
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Chen C, Chen J, Zhang J, Wang S, Zhang W, Liang R, Dai J, Chen C. Ag-Decorated Localized Surface Plasmon-Enhanced Ultraviolet Electroluminescence from ZnO Quantum Dot-Based/GaN Heterojunction Diodes by Optimizing MgO Interlayer Thickness. NANOSCALE RESEARCH LETTERS 2016; 11:480. [PMID: 27797089 PMCID: PMC5085967 DOI: 10.1186/s11671-016-1701-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 10/21/2016] [Indexed: 06/06/2023]
Abstract
We demonstrate the fabrication and characterization of localized surface plasmon (LSP)-enhanced n-ZnO quantum dot (QD)/MgO/p-GaN heterojunction light-emitting diodes (LEDs) by embedding Ag nanoparticles (Ag-NPs) into the ZnO/MgO interface. The maximum enhancement ration of the Ag-NP-decorated LEDs in electroluminescence (EL) is 4.3-fold by optimizing MgO electron-blocking layer thickness. The EL origination was investigated qualitatively in terms of photoluminescence (PL) results. Through analysis of the energy band structure of device and carrier transport mechanisms, it suggests that the EL enhancement is attributed to the increased rate of spontaneous emission and improved internal quantum efficiency induced by exciton-LSP coupling.
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Affiliation(s)
- Cheng Chen
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, Hubei, People's Republic of China
| | - Jingwen Chen
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, Hubei, People's Republic of China
| | - Jun Zhang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, Hubei, People's Republic of China
| | - Shuai Wang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, Hubei, People's Republic of China
| | - Wei Zhang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, Hubei, People's Republic of China
| | - Renli Liang
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, Hubei, People's Republic of China
| | - Jiangnan Dai
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, Hubei, People's Republic of China.
| | - Changqing Chen
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, 430074, Hubei, People's Republic of China
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