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Liu Y, Zhou X, Li P, Yang B, Zhao Z. Design and Growth of Low Resistivity P-Type AlGaN Superlattice Structure. MICROMACHINES 2024; 15:596. [PMID: 38793169 PMCID: PMC11122940 DOI: 10.3390/mi15050596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/03/2024] [Accepted: 04/25/2024] [Indexed: 05/26/2024]
Abstract
This work investigated the impact of periodic thickness and doping region on the doping efficiency of the P-type AlGaN superlattice. In this paper, the band structure of the simulated superlattice was analyzed. The superlattice structure of Al0.1Ga0.3N/Al0.4Ga0.6N, and the AlGaN buffer on the sapphire substrate, achieved a resistivity of ~3.3 Ω·cm. The results indicate that barrier doping and low periodic thickness offer significant advantages in introducing a reduction of the resistivity of P-type AlGaN superlattice structures.
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Affiliation(s)
- Yang Liu
- School of Advanced Materials and Nanotechnology, Xidian University, Xi’an 710071, China; (Y.L.); (B.Y.); (Z.Z.)
| | - Xiaowei Zhou
- School of Advanced Materials and Nanotechnology, Xidian University, Xi’an 710071, China; (Y.L.); (B.Y.); (Z.Z.)
- State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, Xidian University, Xi’an 710071, China
| | - Peixian Li
- School of Advanced Materials and Nanotechnology, Xidian University, Xi’an 710071, China; (Y.L.); (B.Y.); (Z.Z.)
- State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, Xidian University, Xi’an 710071, China
| | - Bo Yang
- School of Advanced Materials and Nanotechnology, Xidian University, Xi’an 710071, China; (Y.L.); (B.Y.); (Z.Z.)
| | - Zhuang Zhao
- School of Advanced Materials and Nanotechnology, Xidian University, Xi’an 710071, China; (Y.L.); (B.Y.); (Z.Z.)
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2
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Xing Z, Zhou Y, Zhang A, Qu Y, Wang F, Liou JJ, Liu Y. Non-heavy doped pnp-AlGaN tunnel junction for an efficient deep-ultraviolet light emitting diode with low conduction voltage. OPTICS EXPRESS 2024; 32:10284-10294. [PMID: 38571244 DOI: 10.1364/oe.520767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 03/01/2024] [Indexed: 04/05/2024]
Abstract
While traditional tunnel junction (TJ) light-emitting diodes (LEDs) can enhance current diffusion and increase hole injection efficiency, their reliance on highly doped AlGaN layers to improve hole tunneling efficiency results in a higher conduction voltage, adversely impacting LED device performance. This paper proposes a non-heavy doped pnp-AlGaN TJ deep ultraviolet (DUV) LED with a low conduction voltage. By inserting the TJ near the active region, between the electron blocking layer and the hole supply layer, the need for heavily doped AlGaN is circumvented. Furthermore, the LED leverages the polarization charge in the pnp-AlGaN TJ layer to decrease the electric field strength, enhancing hole tunneling effects and reducing conduction voltage. The non-heavy doped pnp-AlGaN TJ LED effectively enhances carrier concentration in the quantum well, achieving a more uniform distribution of electrons and holes, thus improving radiative recombination efficiency. Consequently, at an injection current of 120 A/cm2, compared to the traditional structure LED (without TJ), the proposed LED exhibits a 190.7% increase in optical power, a 142.8% increase in maximum internal quantum efficiency (IQE) to 0.85, and a modest efficiency droop of only 5.8%, with a conduction voltage of just 4.1V. These findings offer valuable insights to address the challenges of high heavy doped TJ and elevated conduction voltage in high-performance TJ DUV LEDs.
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3
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Zhao J, Li Q, Tan Q, Liang T, Zhou W, Liu N, Chen Z. Ring geometric effect on the performance of AlGaN-based deep-ultraviolet light-emitting diodes. OPTICS EXPRESS 2024; 32:1275-1285. [PMID: 38297682 DOI: 10.1364/oe.507455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/14/2023] [Indexed: 02/02/2024]
Abstract
In this study, we fabricated and characterized various parallel flip-chip AlGaN-based deep-ultraviolet (DUV) micro-ring LEDs, including changes in ring dimensions as well as the p-GaN-removed region widths at the outer micro-ring, respectively (PRM LEDs). It is revealed that the LED chips with smaller mesa withstand higher current density and deliver considerably higher light output power density (LOPD), under the same proportion of the hole to the entire mesa column (before it is etched into ring) within the limits of dimensions. However, as the ring-shaped mesa decreases, the LOPD begins to decline because of etching damage. Subsequently, at the same external diameter, the optical performance of micro-ring LEDs with varied internal diameters is studied. Meanwhile, the influence of different structures on light extraction efficiency (LEE) is studied by employing a two-dimensional (2D)-finite-difference time-domain (FDTD) method. In addition, the expand of the p-GaN-removed region at the outer micro-ring as well as the corresponding effective light emission region have some influence to LOPD. The PRM-23 LED (with an external diameter of 90 µm, an internal diameter of 22 µm, and a p-GaN-removed region width of 8 µm) has an LOPD of 53.36 W/cm2 with a current density of 650 A/cm2, and an external quantum efficiency (EQE) of 6.17% at 5 A/cm2. These experimental observations provide a comprehensive understanding of the optical and electrical performance of DUV micro-LEDs for future applications.
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Yao Y, Li H, Wang M, Li P, Lam M, Iza M, Speck JS, DenBaars SP, Nakamura S. High external quantum efficiency (6.8%) UV-A LEDs on AlN templates with quantum barrier optimization. OPTICS EXPRESS 2023; 31:28649-28657. [PMID: 37710681 DOI: 10.1364/oe.491622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Accepted: 07/07/2023] [Indexed: 09/16/2023]
Abstract
AlGaN-based UV-A LEDs have wide applications in medical treatment and chemical sensing; however, their efficiencies are still far behind visible LEDs or even shorter wavelengths UV-C counterparts because of the large lattice mismatch between the low-Al-content active region and the AlN substrate. In this report, we investigated the composition and thickness of the quantum barrier in the active region in terms of LED performance. Due to the improved strain management and better carrier confinement, efficient UV-A LEDs (320 nm - 330 nm) with EQEs up to 6.8% were demonstrated, among the highest efficiencies at this wavelength range.
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Adhikari S, Kremer F, Lysevych M, Jagadish C, Tan HH. Core-shell GaN/AlGaN nanowires grown by selective area epitaxy. NANOSCALE HORIZONS 2023; 8:530-542. [PMID: 36825590 DOI: 10.1039/d2nh00500j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
GaN/AlGaN core-shell nanowires with various Al compositions have been grown on GaN nanowire array using selective area metal organic chemical vapor deposition technique. Growth of the AlGaN shell using pure N2 carrier gas resulted in a smooth surface for the nonpolar m-plane sidewalls with superior optical properties, whereas, growth using a mixed N2/H2 carrier gas resulted in a striated surface similar to the commonly observed morphology in the growth of nonpolar III-nitrides. The Al compositions in the AlGaN shells are found to be less than the gas phase input ratio. The systematic reduction in efficiency of Al incorporation in the AlGaN shells with increasing the Al molar flow in the gas phase is attributed to geometric loss, strain-limited Al incorporation, and increased gas phase parasitic reactions. Defect-related luminescence has been observed for AlGaN shells with Al content ≥ 30% and the origin of the defect luminescence has been determined as the (VIII-2ON)1- complex. Microstructural analysis of the AlGaN shells revealed that the dominant defects are partial dislocations. Growth of the nonpolar m-plane AlxGa1-xN/AlyGa1-yN quantum wells on the sidewalls of the GaN nanowires produced arrays with excellent morphology and optical emission, which demonstrated the viability of such a growth scheme for large area efficient ultraviolet LEDs as well as for next generation ultraviolet micro-LEDs.
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Affiliation(s)
- Sonachand Adhikari
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, Australian Capital Territory 2600, Australia.
- Council of Scientific & Industrial Research - Central Electronics Engineering Research Institute, Pilani, Rajasthan 333031, India
| | - Felipe Kremer
- Centre for Advanced Microscopy, The Australian National University, Canberra, Australian Capital Territory 2600, Australia
| | - Mykhaylo Lysevych
- Australian National Fabrication Facility ACT Node, Research School of Physics, The Australian National University, Canberra, Australian Capital Territory 2600, Australia
| | - Chennupati Jagadish
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, Australian Capital Territory 2600, Australia.
- Australian Research Council Centre of Excellence for Transformative Meta-Optical Systems, Research School of Physics, The Australian National University, Canberra, Australian Capital Territory 2600, Australia
| | - Hark Hoe Tan
- Department of Electronic Materials Engineering, Research School of Physics, The Australian National University, Canberra, Australian Capital Territory 2600, Australia.
- Australian Research Council Centre of Excellence for Transformative Meta-Optical Systems, Research School of Physics, The Australian National University, Canberra, Australian Capital Territory 2600, Australia
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6
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Bergmann M, Enslin J, Guttmann M, Sulmoni L, Ploch NL, Hjort F, Kolbe T, Wernicke T, Kneissl M, Haglund Å. Increased Light Extraction of Thin-Film Flip-Chip UVB LEDs by Surface Texturing. ACS PHOTONICS 2023; 10:368-373. [PMID: 36820322 PMCID: PMC9936579 DOI: 10.1021/acsphotonics.2c01352] [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: 08/30/2022] [Indexed: 06/18/2023]
Abstract
Ultraviolet light-emitting diodes (LEDs) suffer from a low wall-plug efficiency, which is to a large extent limited by the poor light extraction efficiency (LEE). A thin-film flip-chip (TFFC) design with a roughened N-polar AlGaN surface can substantially improve this. We here demonstrate an enabling technology to realize TFFC LEDs emitting in the UVB range (280-320 nm), which includes standard LED processing in combination with electrochemical etching to remove the substrate. The integration of the electrochemical etching is achieved by epitaxial sacrificial and etch block layers in combination with encapsulation of the LED. The LEE was enhanced by around 25% when the N-polar AlGaN side of the TFFC LEDs was chemically roughened, reaching an external quantum efficiency of 2.25%. By further optimizing the surface structure, our ray-tracing simulations predict a higher LEE from the TFFC LEDs than flip-chip LEDs and a resulting higher wall-plug efficiency.
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Affiliation(s)
- Michael
A. Bergmann
- Chalmers
University of Technology, Department of Microtechnology
and Nanoscience, 41296Gothenburg, Sweden
| | - Johannes Enslin
- Technische
Universität Berlin, Institute of Solid State Physics, 10623Berlin, Germany
| | - Martin Guttmann
- Technische
Universität Berlin, Institute of Solid State Physics, 10623Berlin, Germany
| | - Luca Sulmoni
- Technische
Universität Berlin, Institute of Solid State Physics, 10623Berlin, Germany
| | - Neysha Lobo Ploch
- Ferdinand-Braun-Institut
gGmbH, Leibniz-Institut für Höchstfrequenztechnik, 12489Berlin, Germany
| | - Filip Hjort
- Chalmers
University of Technology, Department of Microtechnology
and Nanoscience, 41296Gothenburg, Sweden
| | - Tim Kolbe
- Ferdinand-Braun-Institut
gGmbH, Leibniz-Institut für Höchstfrequenztechnik, 12489Berlin, Germany
| | - Tim Wernicke
- Technische
Universität Berlin, Institute of Solid State Physics, 10623Berlin, Germany
| | - Michael Kneissl
- Technische
Universität Berlin, Institute of Solid State Physics, 10623Berlin, Germany
- Ferdinand-Braun-Institut
gGmbH, Leibniz-Institut für Höchstfrequenztechnik, 12489Berlin, Germany
| | - Åsa Haglund
- Chalmers
University of Technology, Department of Microtechnology
and Nanoscience, 41296Gothenburg, Sweden
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7
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Hsu YH, Peng KW, Lin YH, Tseng MC, Lin SH, Shen MC, Wu TZ, Chen Z, Horng RH. Study on the performance of high-voltage deep ultraviolet light-emitting diodes. OPTICS EXPRESS 2022; 30:42241-42248. [PMID: 36366681 DOI: 10.1364/oe.475141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 10/10/2022] [Indexed: 06/16/2023]
Abstract
This study fabricated high-voltage, low-current DUV-LEDs by connecting two devices. Due to better current spreading and the enhanced reflective mirror effect, high-voltage devices present a higher dynamic resistance, emission output power, wall-plug efficiency, external quantum efficiency, and view angle than single traditional devices. The study found that when the injection current was 320 mA, the maximum output power was exhibited at 47.1 mW in the HV sample. The maximum WPE and EQE of high-voltage DUV-LEDs were 2.46% and 5.48%, respectively. Noteworthily, the redshift wavelength shifted from 287.5 to 280.5 nm, less than the traditional device-from 278 to 282 nm. Further, due to the uniform emission patterns in high-voltage devices, the view angle presents 130 degrees at 100 mA input current. In this study, the high-voltage device showed more excellent properties than the traditional device. In particular, it presented a high potential application in high-voltage circuits, which can remove transformers to eliminate extra power consumption.
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8
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Maraj M, Min L, Sun W. Reliability Analysis of AlGaN-Based Deep UV-LEDs. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:nano12213731. [PMID: 36364507 PMCID: PMC9657871 DOI: 10.3390/nano12213731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/24/2022] [Accepted: 10/19/2022] [Indexed: 05/27/2023]
Abstract
The current pandemic crisis caused by SARS-CoV-2 has also pushed researchers to work on LEDs, especially in the range of 220-240 nm, for the purpose of disinfecting the environment, but the efficiency of such deep UV-LEDs is highly demanding for mass adoption. Over the last two decades, several research groups have worked out that the optical power of GaN-based LEDs significantly decreases during operation, and with the passage of time, many mechanisms responsible for the degradation of such devices start playing their roles. Only a few attempts, to explore the reliability of these LEDs, have been presented so far which provide very little information on the output power degradation of these LEDs with the passage of time. Therefore, the aim of this review is to summarize the degradation factors of AlGaN-based near UV-LEDs emitting in the range of 200-350 nm by means of combined optical and electrical characterization so that work groups may have an idea of the issues raised to date and to achieve a wavelength range needed for disinfecting the environment from SARS-CoV-2. The performance of devices submitted to different stress conditions has been reviewed for the reliability of AlGaN-based UV-LEDs based on the work of different research groups so far, according to our knowledge. In particular, we review: (1) fabrication strategies to improve the efficiency of UV-LEDs; (2) the intensity of variation under constant current stress for different durations; (3) creation of the defects that cause the degradation of LED performance; (4) effect of degradation on C-V characteristics of such LEDs; (5) I-V behavior variation under stress; (6) different structural schemes to enhance the reliability of LEDs; (7) reliability of LEDs ranging from 220-240 nm; and (8) degradation measurement strategies. Finally, concluding remarks for future research to enhance the reliability of near UV-LEDs is presented. This draft presents a comprehensive review for industry and academic research on the physical properties of an AlGaN near UV-LEDs that are affected by aging to help LED manufacturers and end users to construct and utilize such LEDs effectively and provide the community a better life standard.
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Affiliation(s)
- Mudassar Maraj
- Research Center for Optoelectronic Materials and Devices, Guangxi Key Laboratory for the Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
| | - Li Min
- Research Center for Optoelectronic Materials and Devices, Guangxi Key Laboratory for the Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
| | - Wenhong Sun
- Research Center for Optoelectronic Materials and Devices, Guangxi Key Laboratory for the Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
- MOE Key Laboratory of New Processing Technology for Non-Ferrous Metals and the Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured Materials, Guangxi University, Nanning 530004, China
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9
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Anomalous Photocurrent Reversal Due to Hole Traps in AlGaN-Based Deep-Ultraviolet Light-Emitting Diodes. MICROMACHINES 2022; 13:mi13081233. [PMID: 36014154 PMCID: PMC9415460 DOI: 10.3390/mi13081233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/26/2022] [Accepted: 07/28/2022] [Indexed: 02/05/2023]
Abstract
The trap states and defects near the active region in deep-ultraviolet (DUV) light-emitting diodes (LED) were investigated through wavelength-dependent photocurrent spectroscopy. We observed anomalous photocurrent reversal and its temporal recovery in AlGaN-based DUV LEDs as the wavelength of illuminating light varied from DUV to visible. The wavelength-dependent photocurrent measurements were performed on 265 nm-emitting DUV LEDs under zero-bias conditions. Sharp near-band-edge (~265 nm) absorption was observed in addition to broad (300–800 nm) visible-range absorption peaks in the photocurrent spectrum, while the current direction of these two peaks were opposite to each other. In addition, the current direction of the photocurrent in the visible wavelength range was reversed when a certain forward bias was applied. This bias-induced current reversal displayed a slow recovery time (~6 h) when the applied forward voltage was removed. Furthermore, the recovery time showed strong temperature dependency and was faster as the sample temperature increased. This result can be consistently explained by the presence of hole traps at the electron-blocking layer and the band bending caused by piezoelectric polarization fields. The activation energy of the defect state was calculated to be 279 meV using the temperature dependency of the recovery time.
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Li Q, Chu C, Wang W, Che J, Shao H, Liu Q, Zhang Y, Zhang ZH. Local dielectric tunnel junction to manage the current distribution for AlGaN-based deep-ultraviolet light-emitting diodes with a thin p-GaN layer. OPTICS LETTERS 2022; 47:3475-3478. [PMID: 35838707 DOI: 10.1364/ol.461732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
In this report, a p+-GaN/SiO2/Ni tunnel junction with a local SiO2 insulation layer is designed to manage the current distribution for commercially structured AlGaN-based deep-ultraviolet light-emitting diodes (DUV LEDs) with a thin p-GaN layer. The experimental and calculated results prove that, besides the increased hole injection at the p+-GaN/SiO2/Ni tunnel junction, the local SiO2 layer produces an in-plane unbalanced energy band in the p-GaN layer for the proposed DUV LEDs, thus modulating the carrier transport paths and increasing the spread of holes. Enhanced optical power is obtained when compared to conventional DUV LEDs. In addition, the influence of the position of the SiO2 insulation layer on the current distribution is also investigated in this work. Placing the SiO2 insulation layer in the middle position of the p+-GaN layer is most helpful for increasing the hole injection efficiency for commercially structured DUV LEDs.
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11
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Sarkar R, Bhunia S, Jana D, Nag D, Chatterjee S, Laha A. Growth of uniform Mg-doped p-AlGaN nanowires using plasma-assisted molecular beam epitaxy technique for UV-A emitters. NANOTECHNOLOGY 2022; 33:384001. [PMID: 35636220 DOI: 10.1088/1361-6528/ac7472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/30/2022] [Indexed: 06/15/2023]
Abstract
In this manuscript, we have shown the growth and extensive structural and optical characteristic of the uniformly Mg-doped Al0.23Ga0.77N (UV-A region,λ∼ 323 nm) nanowire. The Kelvin probe force microscopy was employed to determine the profile of holes in p-type AlGaN nanowires by measuring the work function changes induced by Mg incorporation. The influence of surface band bending on doping concentration has thoroughly been discussed. Our experiment confirms the homogeneous incorporation of Mg throughout the nanowire without any top surface Mg segregation. In this work, we have also demonstrated a comprehensive analysis of acceptor states induced thermal quenching behaviour in the optical transition of Mg-doped AlGaN nanowire. We propose a phenomenological model, based on the rate equation which confirms that achieving higher 'hole' (p-doping) concentration in AlGaN nanowire (>1018cm-3) is more conducive than the planar counterpart if the growth of NWs is carried out at optimized process conditions. This rate equation-based model has also demonstrated the influence of sidewall surface passivation in those AlGaN nanowires.
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Affiliation(s)
- Ritam Sarkar
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai-400076, India
| | - Swagata Bhunia
- Department of Physics, Indian Institute of Technology Bombay, Mumbai-400076, India
| | - Dipankar Jana
- Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India
| | - Dhiman Nag
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai-400076, India
| | - Soumyadip Chatterjee
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai-400076, India
| | - Apurba Laha
- Department of Electrical Engineering, Indian Institute of Technology Bombay, Mumbai-400076, India
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12
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Zhang Q, Parimoo H, Martel E, Zhao S. Vertical semiconductor deep ultraviolet light emitting diodes on a nanowire-assisted aluminum nitride buffer layer. Sci Rep 2022; 12:7230. [PMID: 35508615 PMCID: PMC9068717 DOI: 10.1038/s41598-022-11246-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 04/18/2022] [Indexed: 12/04/2022] Open
Abstract
Vertical light-emitting diodes (LEDs) have many advantages such as uniform current injection, excellent scalability of the chip size, and simple packaging process. Hitherto, however, technologically important semiconductor aluminum gallium nitride (AlGaN) deep ultraviolet (UV) LEDs are mainly through lateral injection. Herein, we demonstrate a new and practical path for vertical AlGaN deep UV LEDs, which exploits a thin AlN buffer layer formed on a nanowire-based template on silicon (Si). Such a buffer layer enables in situ formation of vertical AlGaN deep UV LEDs on Si. Near Lambertian emission pattern is measured from the top surface. The decent reflectivity of Si in the deep UV range makes such a configuration a viable low-cost solution for vertical AlGaN deep UV LEDs. More importantly, the use of such a thin AlN buffer layer can allow an easy transfer of device structures to other carrier wafers for vertical AlGaN deep UV LEDs with ultimately high electrical and optical performance.
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Affiliation(s)
- Qihua Zhang
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, H3A 0E9, Canada
| | - Heemal Parimoo
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, H3A 0E9, Canada
| | - Eli Martel
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, H3A 0E9, Canada
| | - Songrui Zhao
- Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, H3A 0E9, Canada.
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