The influences of sputtered AlN buffer layer on AlInGaN based blue and near‐ultraviolet light emitting diodes

Wang, Jiaxing; Chen, Zhe; Xing, Yuchen; Wang, Lai; Luo, Yi

doi:10.1002/pssa.201600714

Cited by 5 publications

(7 citation statements)

References 22 publications

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“…The microring resonator is fabricated on a 1‐µm‐thick undoped GaN film epitaxially grown on a c ‐plane sapphire substrate by MOCVD, which uses a 50‐nm thick AlN buffer layer formed by magnetron sputtering for improved crystalline quality. [ 12 ] The GaN film thickness is so chosen as to ensure strong light confinement in the waveguide as well as high crystalline quality. The GaN film thickness is so chosen as to ensure strong light confinement in the waveguide as well as high crystalline quality.…”

Section: Resultsmentioning

confidence: 99%

Integrated Gallium Nitride Nonlinear Photonics

Zheng

Sun

Xiong

et al. 2021

Laser & Photonics Reviews

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Gallium nitride (GaN) as a wide bandgap material is widely used in solid-state lighting. Thanks to its high nonlinearity and high refractive index contrast, GaN-on-insulator (GaNOI) is also a promising platform for nonlinear optical applications. Despite its intriguing optical proprieties, nonlinear applications of GaN are rarely studied owing to the relatively high optical loss of GaN waveguides (typically ≈2 dB cm −1 ). In this paper, GaNOI microresonators with intrinsic quality factor over 2.5 million are reported, corresponding to an optical loss of 0.17 dB cm −1 . Parametric oscillation threshold power as low as 6.2 mW is demonstrated, and the experimentally extracted nonlinear index of GaN at telecom wavelengths is estimated to be n 2 = 1.4 × 10 −18 m 2 W −1 , which is several times larger than that of commonly used platform such as Si 3 N 4 , LiNbO 3 , and AlN. Single soliton generation in GaN is implemented by an auxiliary laser pumping scheme, so as to mitigate the high thermorefractive effect in GaN. The large intrinsic nonlinear refractive index, together with its broadband transparency window and high refractive index contrast, make GaNOI a promising platform for chip-scale nonlinear applications.

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Section: Resultsmentioning

confidence: 99%

Integrated Gallium Nitride Nonlinear Photonics

Zheng

Sun

Xiong

et al. 2021

Laser & Photonics Reviews

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“…It has been demonstrated that ex-situ sputtered AlN nucleation layers can improve crystalline quality of GaN films grown by MOCVD and thus characteristics of GaN-based UV LEDs [12][13][14][15][16][17][18][19][20][21][22]. Replacing the in situ MOCVD-grown AlN buffer layer with a sputtered AlN layer reduced full width at half maximum (FWHM) values of (002) and (102) X-ray diffraction (XRD) rocking curves for the GaN layers from 318.0 to 201.1 and from 412.5 to 225.0 arcsec, respectively [12], indicating decrease in dislocation density.…”

Section: Sputtered Aln Buffers For Growth On Flat Sapphire Substratesmentioning

confidence: 99%

“…Sapphire substrates patterned in arrays of cones are commonly used for fabrication of GaN-based LEDs since they help reduce TD density in GaN and enhance light extraction [35,36]. Replacing the in situ MOCVD-grown AlN [12,13] or GaN buffer layers [14][15][16][17][18][19]34] on such substrates with an ex situ sputtered AlN layer was found to reduce the TD density in GaN layers and improve LED characteristics. For example, Yu et al [34] reported that the total dislocation density in the GaN film grown by MOCVD on a sputtered AlN nucleation layer (2.2×10 8 cm −2 ) was about 42% fewer than that in the sister GaN layer on an in situ GaN nucleation layer (3.7×10 8 cm −2 ), with the individual reduction in densities of screw, edge, and mixed-type dislocations by 17%, 29%, and 61%, respectively.…”

Section: Sputtered Aln Buffers For Growth On Patterned Sapphire Subst...mentioning

confidence: 99%

Emergence of high quality sputtered III-nitride semiconductors and devices

Izyumskaya¹,

Avrutin²,

Ding³

et al. 2019

Semicond. Sci. Technol.

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This article provides an overview of recent development of sputtering method for high-quality III-nitride semiconductor materials and devices. Being a mature deposition technique widely employed in semiconductor industry, sputtering offers many advantages such as low cost, relatively simple equipment, non-toxic raw materials, low process temperatures, high deposition rates, sharp interfaces, and possibility of deposition on large-size substrates, including amorphous and flexible varieties. This review covers two major research directions: (1) ex situ sputtered AlN buffers to be used for subsequent growth of GaN-based structures by conventional techniques, such as metal-organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), or molecular beam epitaxy (MBE), and (2) deposition of the entire III-nitride layered stacks and device structures by sputtering. Replacing conventional in situ GaN or AlN buffer layers with ex situ sputtered AlN buffers for MOCVD, HVPE, or MBE growth of IIInitride films on sapphire and silicon substrates results in the improved crystal quality through reduction in dislocation density and residual strain. Extensive efforts in the field of sputter deposition of III-nitrides resulted in crystalline quality of sputtered III-nitride films compatible with that of MOCVD and MBE grown layers despite the lower temperatures used in sputtering. For example, sputtering techniques made it possible to achieve GaN layers heavily doped with Si and Ge to electron concentrations in mid-10 20 cm −3 range with mobilities exceeding 100 cm 2 V −1 s −1 , resulting in conductivities as high as those of benchmark transparent conducting oxides such as indium tin oxide (ITO). For moderate levels of doping with Si, mobilities comparable to state-of-the-art MOCVD-grown material have been demonstrated (up to ∼1000 cm 2 V −1 s −1 ). The first promising results have been reported for devices (light emitters and field effect transistors) entirely produced by sputtering.

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“…This is because the IQE of near-UV LED is more sensitive to the dislocation density [ 87 , 88 ]. If instead of GaN buffer layer a sputtered AlN buffer layer is applied to lower the dislocation density [ 89 ], the IQE can be further improved to approach or even exceed that of blue one. However, it does not change the variation trend of IQE and the conclusion in following discussion.…”

Section: Carrier Lifetime Measurementmentioning

confidence: 99%

“…These reasons lead to the differences of carrier lifetimes in near-UV, blue, and green LEDs shown in Figure 5 b. Even if the non-radiative recombination of the near-UV LED can be further suppressed, it will still hold the shortest carrier lifetime due to its weakest QCSE [ 89 ].…”

Section: Carrier Lifetime Measurementmentioning

confidence: 99%

A Review on Experimental Measurements for Understanding Efficiency Droop in InGaN-Based Light-Emitting Diodes

Wang

Jin

et al. 2017

Materials

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Efficiency droop in GaN-based light emitting diodes (LEDs) under high injection current density perplexes the development of high-power solid-state lighting. Although the relevant study has lasted for about 10 years, its mechanism is still not thoroughly clear, and consequently its solution is also unsatisfactory up to now. Some emerging applications, e.g., high-speed visible light communication, requiring LED working under extremely high current density, makes the influence of efficiency droop become more serious. This paper reviews the experimental measurements on LED to explain the origins of droop in recent years, especially some new results reported after 2013. Particularly, the carrier lifetime of LED is analyzed intensively and its effects on LED droop behaviors are uncovered. Finally, possible solutions to overcome LED droop are discussed.

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The influences of sputtered AlN buffer layer on AlInGaN based blue and near‐ultraviolet light emitting diodes

Cited by 5 publications

References 22 publications

Integrated Gallium Nitride Nonlinear Photonics

Integrated Gallium Nitride Nonlinear Photonics

Emergence of high quality sputtered III-nitride semiconductors and devices

A Review on Experimental Measurements for Understanding Efficiency Droop in InGaN-Based Light-Emitting Diodes

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