Progress in periodically oriented III-nitride materials

Hite, Jennifer K.

doi:10.1016/j.jcrysgro.2016.08.042

Cited by 9 publications

(11 citation statements)

References 48 publications

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“…The fabrication of LPS depends on patterning of the underlying LT-AlN buffer deposited on sapphire. Generally, a III-nitride thin film grown on AlN buffer leads to III-polarity, while a film grown on bare sapphire with proper nitridation results in N-polarity . However, the control of the thin film quality and interface abruptness of LPS, especially high-Al-content AlGaN-based LPS, is not trivial.…”

Section: Resultsmentioning

confidence: 99%

“…Generally, a III-nitride thin film grown on AlN buffer leads to III-polarity, while a film grown on bare sapphire with proper nitridation results in N-polarity. 14 However, the control of the thin film quality and interface abruptness of LPS, especially high-Alcontent AlGaN-based LPS, is not trivial. Prior to hightemperature epitaxial growth, the patterned AlN buffer went through H 2 annealing followed by a nitridation process under an NH 3 atmosphere.…”

Section: Resultsmentioning

confidence: 99%

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Polarity Control and Nanoscale Optical Characterization of AlGaN-Based Multiple-Quantum-Wells for Ultraviolet C Emitters

Jiang

Dai

et al. 2020

ACS Appl. Nano Mater.

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Optical properties of AlGaN UVC multiple-quantum-wells (MQWs) with nanoscale inverted polarity domains are strongly related to polar surfaces and nanoscale structures. In this work, the impact of pregrowth nitridation of the sapphire substrate on the polarity control of UVC MQW is highlighted, and the optical properties of III- and N-polar domains were distinguished. Nanoscale cathodoluminescence peak separation of more than 30 nm is observed in lateral-polarity-structure (LPS) UVC MQWs, which is ascribed to the potential minima induced by the local variation of QW thickness and Ga enrichment inside N-polar domains. After an AlGaN/AlN superlattice is inserted and the V/III ratio is enhanced during growth, the surface morphology of the N-polar domain is greatly improved, leading to a single-peak emission at a wavelength of 275 nm in both the III- and N-polar domains, and a 10-fold stronger peak intensity at the inversion domain boundary. Such understandings on the polar surface optimization and underlying reasons of peak separation enable rational design for efficient UVC emitters with improved performance.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Polarity Control and Nanoscale Optical Characterization of AlGaN-Based Multiple-Quantum-Wells for Ultraviolet C Emitters

Jiang

Dai

et al. 2020

ACS Appl. Nano Mater.

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“…Polarity control can be realized by either patterning of LT buffers and subsequent nitridation [23,24], or changing the deposition temperature of AlN buffers prior to growth [25]. However, since the AlN buffer can only be deposited under one particular temperature during one growth process, the latter technique is not suitable for LPS fabrication.…”

Section: Fabrication Of Lateral Polarity Structurementioning

confidence: 99%

Polarity control and fabrication of lateral polarity structures of III-nitride thin films and devices: progress and prospects

Guo

Chen

et al. 2020

J. Phys. D: Appl. Phys.

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Due to their non-centrosymmetric crystal orientation, wurtzite III-nitride crystals have two distinct orientations, i.e. III-polar and N-polar along the c-axis. Extensive effort has been devoted to polarity control and the characterization of III-nitride thin films. Both III-polar and N-polar films possess some unique features. By taking full advantage of both III and N-polar domains in a single structure, a lateral polarity structure (LPS), where III-polar and N-polar domains are grown side-by-side simultaneously on the wafer, has attracted great interest. In this review, recent progress in the design and fabrication of III-nitride LPS on various substrates is summarized. The structural, optical and electronic properties of III-nitride thin films incorporating LPS are discussed, with special attention paid to the interface between adjacent domains. Various techniques to qualitatively and quantitatively identify the polarity domains are provided, and their applications in optoelectronic and electronic devices including light-emitting-diodes, nonlinear frequency doubling waveguides, Schottky-barrier-diodes, etc, are intensively elaborated on. Finally, challenges related to the development of LPS-based devices and future perspectives are presented.

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“…[13] A macroscale lateral polarity structure (LPS) was fabricated by substrate patterning followed by epitaxial growth through metal-organic chemical vapor deposition (MOCVD) with III-and N-polarity domains simultaneously grown side-by-side. [14] Utilizing this structure, Collazo et al reported a depletion-mode metalsemiconductor field-effect transistor (MESFET) on LPS-GaN with improvement in contact resistance. [15] Sheikhi et al reported the usage of LPS-GaN in the fabrication of Schottky barrier diode (SBD) with smaller on-state resistance and larger rectification ratio.…”

Section: Introductionmentioning

confidence: 99%

“…A few works have been carried out so far. [14,[16][17][18] A recent study of our group demonstrated that by scaling down the size of both III-and N-polar domains to only several micrometers, and incorporating LPS into AlGaN/GaN multiple quantum wells (MQWs), dramatically different optical behaviors were identified. [19] Higher luminescence intensity was observed in N-polar than in III-polar domains, which can be ascribed to thickness fluctuations in N-polar domains as previously demonstrated by transmission electron microscopy (TEM).…”

Section: Introductionmentioning

confidence: 99%

Evidence of Carrier Localization in AlGaN/GaN‐Based UV Multiple Quantum Wells with Opposite Polarity Domains Provided by Nanoscale Imaging

Cui

Guo

et al. 2021

Physica Rapid Research Ltrs

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AlGaN-based multiple quantum wells (MQWs) incorporating opposite polarity domains are grown by metal-organic chemical vapor deposition (MOCVD). A direct demonstration of the carrier localization effect is provided by a combination analysis of space-resolved luminescence peak position and Ga/Al composition distribution. Furthermore, through Raman spectroscopy, it is found that compressive strain plays a key role in improving the optical properties of UV-MQWs despite the inferior crystalline quality in the N-polar domains. This suggests that incorporating sub-micrometer-scale polarity domains in the MQWs is promising for the development of efficient UV emitters.

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Progress in periodically oriented III-nitride materials

Cited by 9 publications

References 48 publications

Polarity Control and Nanoscale Optical Characterization of AlGaN-Based Multiple-Quantum-Wells for Ultraviolet C Emitters

Polarity Control and Nanoscale Optical Characterization of AlGaN-Based Multiple-Quantum-Wells for Ultraviolet C Emitters

Polarity control and fabrication of lateral polarity structures of III-nitride thin films and devices: progress and prospects

Evidence of Carrier Localization in AlGaN/GaN‐Based UV Multiple Quantum Wells with Opposite Polarity Domains Provided by Nanoscale Imaging

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