Room-temperature operation of AlGaN ultraviolet-B laser diode at 298 nm on lattice-relaxed Al<sub>0.6</sub>Ga<sub>0.4</sub>N/AlN/sapphire

Sato, Kosuke; Yasue, Shinji; Yamada, Kazuki; Omori, Tomoya; Ishizuka, Sayaka; Teramura, Shohei; Ogino, Yousuke; Iwayama, Sho; Miyake, Hideto; Takeuchi, Tetsuya; Kamiyama, Satoshi; Akasaki, Isamu

doi:10.35848/1882-0786/ab7711

Cited by 83 publications

(65 citation statements)

References 30 publications

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“…More recently, UVB laser diodes of λ = 298 nm have been demonstrated on AlN/sapphire templates with a composition-graded p-AlGaN cladding layer. The reported device had a threshold current density of 67 kA/cm 2 at room temperature under pulse operations [220]. A UVB laser of a lower threshold (~25 kA/cm 2 ) was reported by the same group using an Al 0.6 Ga 0.4 N/AlN/sapphire substrate [221].…”

Section: Nitride Based Ultraviolet Laser Diodesmentioning

confidence: 82%

III-Nitride Light-Emitting Devices

et al. 2021

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III-nitride light-emitting devices have been subjects of intense research for the last several decades owing to the versatility of their applications for fundamental research, as well as their widespread commercial utilization. Nitride light-emitters in the form of light-emitting diodes (LEDs) and lasers have made remarkable progress in recent years, especially in the form of blue LEDs and lasers. However, to further extend the scope of these devices, both below and above the blue emission region of the electromagnetic spectrum, and also to expand their range of practical applications, a number of issues and challenges related to the growth of materials, device design, and fabrication need to be overcome. This review provides a detailed overview of nitride-based LEDs and lasers, starting from their early days of development to the present state-of-the-art light-emitting devices. Besides delineating the scientific and engineering milestones achieved in the path towards the development of the highly matured blue LEDs and lasers, this review provides a sketch of the prevailing challenges associated with the development of long-wavelength, as well as ultraviolet nitride LEDs and lasers. In addition to these, recent progress and future challenges related to the development of next-generation nitride emitters, which include exciton-polariton lasers, spin-LEDs and lasers, and nanostructured emitters based on nanowires and quantum dots, have also been elucidated in this review. The review concludes by touching on the more recent topic of hexagonal boron nitride-based light-emitting devices, which have already shown significant promise as deep ultraviolet and single-photon emitters.

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Section: Nitride Based Ultraviolet Laser Diodesmentioning

confidence: 82%

III-Nitride Light-Emitting Devices

et al. 2021

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“…In particular, p-type DPD has been successful in III-nitride light-emitting devices because of its high conductivity and high optical transparency compared with those of Mg-doped (Al)GaN. [25][26][27][28] The features mentioned above are also attractive for application to power devices. Although fundamental understandings of p-n junctions are important for the application to power devices, there are few reports on experimental demonstrations of dopant-free p-n junctions formed by DPD, and detailed characteristics of the junctions are still unclear.…”

Section: Introductionmentioning

confidence: 99%

Space–Charge Profiles and Carrier Transport Properties in Dopant‐Free GaN‐Based p‐n Junction Formed by Distributed Polarization Doping

Kumabe

Kawasaki

Watanabe

et al. 2022

Physica Rapid Research Ltrs

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Herein, the operation of dopant‐free GaN‐based p‐n junctions formed by distributed polarization doping (DPD) is experimentally demonstrated and their space charge profiles and carrier transport properties are investigated. The device exhibits ideal space charge profiles explained by polarization effects and demonstrates the excellent controllability of DPD. In addition, it shows rectification and electroluminescence under forward‐biased conditions. The carrier transport properties could be explained by the conventional recombination/diffusion model used for impurity‐doped p‐n junctions. Repeatable breakdowns are also observed in all devices and the temperature‐dependent breakdown voltages reveal that the breakdowns are caused by avalanche multiplication, which is also the same as those reported in impurity‐doped GaN p‐n diodes. These results indicate that DPD is a promising doping technology for GaN‐based power devices overcoming any issues associated with conventional impurity doping.

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“…There are some reports of deep UV optoelectronic devices with very thick n-AlGaN [4][5][6], showing that it is feasible to produce high-WPE devices using this approach, but there are some risks to growing n-AlGaN to thicknesses greater than 1 µm. First, any optical absorption will be increased with layer thickness.…”

Section: Introductionmentioning

confidence: 99%

Highly Conductive n-Al0.65Ga0.35N Grown by MOCVD Using Low V/III Ratio

et al. 2021

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Highly conductive silicon-doped AlGaN and ohmic contacts are needed for deep-UV LEDs and ultrawide bandgap electronics. We demonstrate improved n-Al0.65Ga0.35N films grown by metal–organic chemical vapor deposition (MOCVD) on sapphire substrates using a low V/III ratio (V/III = 10). A reduced V/III ratio improves repeatability and uniformity by allowing a wider range of silicon precursor flow conditions. AlxGa1−xN:Si with x > 0.5 typically has an electron concentration vs. silicon concentration trend that peaks at a particular “knee” value before dropping sharply as [Si] continues to increase (self-compensation). The Al0.65Ga0.35N:Si grown under the lowest V/III conditions in this study does not show the typical knee behavior, and instead, it has a flat electron concentration trend for [Si] > 3 × 1019 cm−3. Resistivities as low as 4 mΩ-cm were achieved, with corresponding electron mobility of 40 cm2/Vs. AFM and TEM confirm that surface morphology and dislocation density are not degraded by these growth conditions. Furthermore, we report vanadium-based ohmic contacts with a resistivity of 7 × 10−5 Ω-cm2 to AlGaN films grown using a low V/III ratio. Lastly, we use these highly conductive silicon-doped layers to demonstrate a 284 nm UV LED with an operating voltage of 7.99 V at 20 A/cm2, with peak EQE and WPE of 3.5% and 2.7%, respectively.

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Room-temperature operation of AlGaN ultraviolet-B laser diode at 298 nm on lattice-relaxed Al_0.6Ga_0.4N/AlN/sapphire

Cited by 83 publications

References 30 publications

III-Nitride Light-Emitting Devices

III-Nitride Light-Emitting Devices

Space–Charge Profiles and Carrier Transport Properties in Dopant‐Free GaN‐Based p‐n Junction Formed by Distributed Polarization Doping

Highly Conductive n-Al0.65Ga0.35N Grown by MOCVD Using Low V/III Ratio

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Room-temperature operation of AlGaN ultraviolet-B laser diode at 298 nm on lattice-relaxed Al0.6Ga0.4N/AlN/sapphire

Cited by 83 publications

References 30 publications

III-Nitride Light-Emitting Devices

III-Nitride Light-Emitting Devices

Space–Charge Profiles and Carrier Transport Properties in Dopant‐Free GaN‐Based p‐n Junction Formed by Distributed Polarization Doping

Highly Conductive n-Al0.65Ga0.35N Grown by MOCVD Using Low V/III Ratio

Contact Info

Product

Resources

About

Room-temperature operation of AlGaN ultraviolet-B laser diode at 298 nm on lattice-relaxed Al_0.6Ga_0.4N/AlN/sapphire