Photoluminescence measurements on cubic InGaN layers deposited on a SiC substrate

Pacheco‐Salazar, D. G.; Leite, J. R.; Cerdeira, F.; Menêses, E.A.; Li, S F; As, D. J.; Lischka, K.

doi:10.1088/0268-1242/21/7/003

Cited by 11 publications

(6 citation statements)

References 27 publications

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“…Ultimately, the anisotropic stress of the c -GaN confined in a 1D groove from XRD and PL emphasizes its significance for the electronic properties that must be counted in the design of low-dimensional III–N devices. The latter so-called blue luminescence at ∼2.8 eV could be defect-related transitions that have been reported previously. , In energy, this peak is very similar to that reported recently, which was interpreted as the donor-to-acceptor transition originated from a nominally undoped c -GaN by the h–c transition. , …”

Section: Results and Discussionsupporting

confidence: 88%

Elastic Variation of Quasi-One-Dimensional Cubic-Phase GaN at Nanoscale

Lee

Peterson

Jiang

et al. 2019

Crystal Growth & Design

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The elastic properties of the cubic (c-) phase GaN confined in a nanoscale one-dimensional (1D) v-grooved Si(001) substrate are investigated. Along a ∼900 nm-wide v-groove formed with two facing Si(111)-type facets, submicrometer-wide c-GaN is achieved by the hexagonal-to c-phase (h−c) transition from the h-GaN which plays the role of an interlayer in its epitaxy on Si. The resulting nonplanar stack of c-GaN/h-GaN on Si has complicated stress distribution. This work focuses on the elastic properties the c-GaN, which are critically affected by its low dimensionality, and presents experimental evidence for it with an analytical stress modeling. A reciprocal lattice map reveals that the c-GaN in each groove consists of several micrometer-long single crystals which are microscopically tilted from each other in their serial coalescence, as its unit structures. The corresponding micrometer-scale lateral correlation length, d c , results from the h−c transition that is interrupted by the groove imperfections generated in fabrication and the stress fluctuation in the misoriented h-GaN interlayer. The modeling suggests that d c is long enough to induce the tensile stress, dominating with the longitudinal strain parallel to the groove which is ∼2.5× the transverse strain, and the c-GaN can be regarded as a serial array of a quasi-1D unit structures which retain such anisotropic stress resulting from their geometrical shape. The Poisson ratio of the c-GaN in <110> is ∼0.21, close to 0.26 from a theoretical prediction. The variation of the c-phase bandgap under the given tensile stress is addressed.

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Section: Results and Discussionsupporting

confidence: 88%

Elastic Variation of Quasi-One-Dimensional Cubic-Phase GaN at Nanoscale

Lee

Peterson

Jiang

et al. 2019

Crystal Growth & Design

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“…A quadratic bowing coefficient and the binary emission energies E (GaN) = 3.24 eV , and E (InN) = 0.69 eV describe the entire composition range according to E ( In x Ga 1 − x N ) = E ( GaN ) ( 1 − x ) + E ( InN ) italicx − b italicx ( 1 − x ) A bowing coefficient of b = 2.4 eV yields the best fit (dashed black line in Figure b). This value is slightly lower than the bowing of the emission energy in hexagonal In x Ga 1– x N ( b ≈ 2.8 eV). , Compared to other cubic In x Ga 1– x N epilayers, the emission energies reported here for low indium content ( x (In) < 0.3) align rather well with other bulk-like thin film samples. ,− For larger alloy compositions (0.3 < x (In) < 0.5), reports on the optical properties of c-In x Ga 1– x N are sparse. We observe emission peaks at significantly lower energies than those of other c-In x Ga 1– x N layers − or multi quantum wells. − The most recent study, ref , determines a significantly smaller bowing of b = 1.4 eV by ellipsometry measurements, which might be caused by the somewhat higher energy values that are measured in the very highly alloyed samples with x (In) > 0.9 and the lack of data for x (In) > 0.5 (see Figure b).…”

Section: Resultssupporting

confidence: 67%

Overcoming the Miscibility Gap of GaN/InN in MBE Growth of Cubic In_xGa_1–xN

Zscherp,

Jentsch,

Müller

et al. 2023

ACS Appl. Mater. Interfaces

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The lack of internal polarization fields in cubic group-III nitrides makes them promising arsenic-free contenders for next-generation high-performance electronic and optoelectronic applications. In particular, cubic In x Ga 1−x N semiconductor alloys promise band gap tuning across and beyond the visible spectrum, from the near-ultraviolet to the near-infrared. However, realization across the complete composition range has been deemed impossible due to a miscibility gap corresponding to the amber spectral range. In this study, we use plasma-assisted molecular beam epitaxy (PAMBE) to fabricate cubic In x Ga 1−x N films on c-GaN/AlN/3C-SiC/Si template substrates that overcome this challenge by careful adjustment of the growth conditions, conclusively closing the miscibility gap. X-ray diffraction reveals the composition, phase purity, and strain properties of the In x Ga 1−x N films. Scanning transmission electron microscopy reveals a CuPt-type ordering on the atomistic scale in highly alloyed films with x(In) ≈ 0.5. Layers with much lower and much higher indium content exhibit statistical distributions of the cations Ga and In. Notably, this CuPt-type ordering results in a spectrally narrower emission compared to that of statistically disordered zincblende materials. The emission energies of the films range from 3.24 to 0.69 eV and feature a quadratic bowing parameter of b = 2.4 eV. In contrast, the LO-like phonon modes that are observed by Raman spectroscopy exhibit a one-mode behavior and shift linearly from c-GaN to c-InN.

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“…However, solely a raw comparison of accuracy, as done before, is not totally fair: one approach, could, for example, require a much larger computational effort to reach that level of accuracy, and when deciding on which approach should be employed one should be aware of the computational price beforehand. Therefore, we also compare the computational resources (average time, T, and memory, M) demanded by each [87]; c, [88]; d, [89]; e, [90]; f, [91]; g, [92]; h, [93]; i, [94].…”

Section: Accuracy and Computational Resourcesmentioning

confidence: 99%

Comparing LDA-1/2, HSE03, HSE06 andG₀W₀approaches for band gap calculations of alloys

Pelá

Marques

Teles

2015

J. Phys.: Condens. Matter

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It has long been known that the local density approximation and the generalized gradient approximation do not furnish reliable band gaps, and one needs to go beyond these approximations to reliably describe these properties. Among alternatives are the use of hybrid functionals (HSE03 and HSE06 being popular), the GW approximation or the recently proposed LDA-1/2 method. In this work, we compare rigorously the performance of these four methods in describing the band gaps of alloys, employing the generalized quasi-chemical approach to treat the disorder of the alloy and to obtain judiciously the band gap for the entire compositional range. Zincblende InGaAs and InGaN were chosen as prototypes due to their importance in optoelectronic applications. The comparison between these four approaches was guided both by the agreement between the predicted band gap and the experimental one, and by the demanded computational effort (time and memory). We observed that the HSE06 method provided the most accurate results (in comparison with experiments), whereas, surprisingly, the LDA-1/2 method gave the best compromise between accuracy and computational resources. Due to its low computational cost and good accuracy, we decided to double the supercell used to describe the alloys, and employing LDA-1/2 we observed that the bowing parameter changed remarkably, only agreeing with the measured one for the larger supercell, where LDA-1/2 plays an important role.

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Photoluminescence measurements on cubic InGaN layers deposited on a SiC substrate

Cited by 11 publications

References 27 publications

Elastic Variation of Quasi-One-Dimensional Cubic-Phase GaN at Nanoscale

Elastic Variation of Quasi-One-Dimensional Cubic-Phase GaN at Nanoscale

Overcoming the Miscibility Gap of GaN/InN in MBE Growth of Cubic In_xGa_1–xN

Comparing LDA-1/2, HSE03, HSE06 andG₀W₀approaches for band gap calculations of alloys

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Photoluminescence measurements on cubic InGaN layers deposited on a SiC substrate

Cited by 11 publications

References 27 publications

Elastic Variation of Quasi-One-Dimensional Cubic-Phase GaN at Nanoscale

Elastic Variation of Quasi-One-Dimensional Cubic-Phase GaN at Nanoscale

Overcoming the Miscibility Gap of GaN/InN in MBE Growth of Cubic InxGa1–xN

Comparing LDA-1/2, HSE03, HSE06 andG0W0approaches for band gap calculations of alloys

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Product

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Overcoming the Miscibility Gap of GaN/InN in MBE Growth of Cubic In_xGa_1–xN

Comparing LDA-1/2, HSE03, HSE06 andG₀W₀approaches for band gap calculations of alloys