Detailed analysis of Ga-rich current pathways created in an n-Al<sub>0.7</sub>Ga<sub>0.3</sub>N layer grown on an AlN template with dense macrosteps

Nagasawa, Yosuke; Hirano, Akira; Ippommatsu, Masamichi; Sako, Hideki; Hashimoto, Ai; Sugie, Ryuichi; Honda, Yoshio; Amano, Hiroshi; Akasaki, Isamu; Kojima, Kazunobu; Chichibu, Shigefusa F.

doi:10.35848/1882-0786/abcb49

Cited by 9 publications

(14 citation statements)

References 35 publications

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“…It has been reported the AlN molar fraction observed by TEM-EDS possesses a residual error from the value observed by STEM coupled with Rutherford backscattering. 35) Figures 5(a) and 5(b) show cross-sectional SEM images around the exfoliated interface before the LLO and its corresponding CL panchromatic image. Figures 5(c) and 5(d) present the CL intensity maps obtained from the line profiles for lines I and II in Fig.…”

Section: (F)mentioning

confidence: 99%

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Centimeter-scale laser lift-off of an AlGaN UVB laser diode structure grown on nano-patterned AlN

Shojiki

Shimokawa

Iwayama

et al. 2022

Appl. Phys. Express

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The centimeter-scale laser lift-off (LLO) of a UVB laser diode structure on nano-patterned AlN was demonstrated by using a 257 nm pulsed laser. The mechanism of this LLO, which can be used for vertical light-emitting device fabrications, was analyzed in detail from the structural and optical properties. The large-area high-yield LLO without cracks was found to be enabled by taking advantage of the intentional in-plane periodic and nanometer-scale inhomogeneous distribution of the AlN molar fraction in the AlGaN layer introduced by growing AlGaN on nano-patterned AlN.

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Section: (F)mentioning

confidence: 99%

“…5(e)] and concave [Fig. 5(f)] regions were estimated to 0.56 and 0.54 with bowing parameters of 1.0, 35) respectively. The AlN molar fraction of u-AlGaN on the convex region [Fig.…”

Section: (F)mentioning

confidence: 99%

Centimeter-scale laser lift-off of an AlGaN UVB laser diode structure grown on nano-patterned AlN

Shojiki

Shimokawa

Iwayama

et al. 2022

Appl. Phys. Express

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“…Our recent analytical studies on AlGaN layers with dense macrosteps revealed the generation of metastable Al n/12 Ga 1−n/12 N (n is an integer from 2 to 10) along macrostep edgelines. Results from our previous works indicated that the atomic configurations of Al n/12 Ga 1−n/12 N should have 2 or fewer monolayer (ML) configurations [31][32][33][34][35][36][37][38]. Hereafter, n ML, represents the periodicity of the structure in the c[0001] direction, where n is the number of atomic layers in a unit cell.…”

Section: Introductionmentioning

confidence: 99%

Metastable atomic-ordered configurations for Al_1/2Ga_1/2N predicted by Monte-Carlo method based on first-principles calculations

Gueriba,

Mizuseki,

Cadatal-Raduban

et al. 2023

J. Phys.: Condens. Matter

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Metastability of Al n /12Ga1−n/12N (n= 2–10: integer) with the 1–2 monolayer (ML) in-plane configuration towards the c [0001] direction has been demonstrated recently. To theoretically explain the existence of these metastable structures, relatively large calculation cells are needed. However, previous calculations were limited to the use of small calculation cell sizes to estimate the local potential depth (Δσ) of ordered Al1/2Ga1/2N models. In this work, we were able to evaluate large calculation cells based on the interaction energies between proximate Al atoms (δE Al–Al) in AlGaN alloys. To do this, δE Al–Al values were estimated by first-principles calculations (FPCs) using a (5a 1 × 5a 2 × 5c) cell. Next, a survey of the possible ordered configurations using various large calculation cell models was performed using the estimated δE Al–Al values and the Monte-Carlo method. Then, various Δσ values were estimated by FPCs and compared with the configurations previously reported by other research groups. We found that the ordered configuration obtained from the (4a 1 × 2a 2 × 1c) calculation cell (C 42) has the lowest Δσ of −9.3 meV/cation and exhibited an in-plane configuration at the c(0001) plane having (–Al–Al–Ga–Ga–) and (–Al–Ga–) sequence arrangements observed along the m 1 1 ˉ 00 planes. Hence, we found consistencies between the morphology obtained from experiment and the shape of the primitive cell based on our numerical calculations.

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“…[ 13–15 ] A systematic study of this phenomenon by different groups using both technologies revealed a wide range of ordering from a simple bilayer (1:1) period to much longer, up to 12 ML and even 30–40 nm or incommensurate periods. [ 16–20 ] There are several points of view on the physical driving forces of this phenomenon in AlGaN layers.…”

Section: Introductionmentioning

confidence: 99%

“…[13][14][15] A systematic study of this phenomenon by different groups using both technologies revealed a wide range of ordering from a simple bilayer (1:1) period to much longer, up to 12 ML and even 30-40 nm or incommensurate periods. [16][17][18][19][20]…”

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Monolayer‐Range Compositional Modulations in Al_xGa_1−xN_{(x = 0.6–0.75)} Layers Grown Using Plasma‐Assisted Molecular Beam Epitaxy under Me‐Rich Conditions with an Off‐Centered Spatial Distribution of Activated Nitrogen Flux

Jmerik

Нечаев

Yagovkina

et al. 2022

Physica Status Solidi (a)

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The different types of compositional inhomogeneities in ternary alloys of III-nitrides play an important role in the functioning of optoelectronics and electronic devices based on these materials. The fast development of highly efficient light-emitting diodes (LEDs) based on InGaN/GaN quantum-well (QW) structures was mainly determined by the inhomogeneous In distribution in the wells, which leads to the formation of a potential relief with local minima that localize charge carriers (localization states). As a result, this increases the quantum yield due to suppressing the lateral transport of charge carriers to such nonradiative recombination centers as threading dislocations. [1] Fluctuations in the In content in InGaN alloys are determined mainly by the thermodynamic instability of this compound at an InN mole concentration above %8À20 mol%, which results in the development of phase separation. [2,3] In addition, the compositional inhomogeneities in InGaN layers and QWs are determined by indium incorporation and its segregation effect. [4] Binary and ternary (Al,Ga)N compounds are basic materials for ultraviolet (UV) optoelectronics and high-power/frequency devices with numerous applications in various fields. [5][6][7][8] AlGaN layers also exhibit compositional inhomogeneities and ordering in a wide range of different scales from 1 monolayer (ML) to several tens of nanometers. The ordering has been observed in AlGaN layers grown by plasma-assisted molecular beam epitaxy (PA MBE) or metalÀorganic chemical vapor deposition (MOCVD). [9][10][11][12] Already in the first papers published by Moustakas's group, a strong dependence of the ordering on the PA MBE stoichiometric conditions, determined by III/N flux ratio, was found. [13][14][15] A systematic study of this phenomenon by different groups using both technologies revealed a wide range of ordering from a simple bilayer (1:1) period to much longer, up to 12 ML and even 30-40 nm or incommensurate periods. [16][17][18][19][20]

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Detailed analysis of Ga-rich current pathways created in an n-Al_0.7Ga_0.3N layer grown on an AlN template with dense macrosteps

Cited by 9 publications

References 35 publications

Centimeter-scale laser lift-off of an AlGaN UVB laser diode structure grown on nano-patterned AlN

Centimeter-scale laser lift-off of an AlGaN UVB laser diode structure grown on nano-patterned AlN

Metastable atomic-ordered configurations for Al_1/2Ga_1/2N predicted by Monte-Carlo method based on first-principles calculations

Monolayer‐Range Compositional Modulations in Al_xGa_1−xN_{(x = 0.6–0.75)} Layers Grown Using Plasma‐Assisted Molecular Beam Epitaxy under Me‐Rich Conditions with an Off‐Centered Spatial Distribution of Activated Nitrogen Flux

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Detailed analysis of Ga-rich current pathways created in an n-Al0.7Ga0.3N layer grown on an AlN template with dense macrosteps

Cited by 9 publications

References 35 publications

Centimeter-scale laser lift-off of an AlGaN UVB laser diode structure grown on nano-patterned AlN

Centimeter-scale laser lift-off of an AlGaN UVB laser diode structure grown on nano-patterned AlN

Metastable atomic-ordered configurations for Al1/2Ga1/2N predicted by Monte-Carlo method based on first-principles calculations

Monolayer‐Range Compositional Modulations in AlxGa1−xN(x = 0.6–0.75) Layers Grown Using Plasma‐Assisted Molecular Beam Epitaxy under Me‐Rich Conditions with an Off‐Centered Spatial Distribution of Activated Nitrogen Flux

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Detailed analysis of Ga-rich current pathways created in an n-Al_0.7Ga_0.3N layer grown on an AlN template with dense macrosteps

Metastable atomic-ordered configurations for Al_1/2Ga_1/2N predicted by Monte-Carlo method based on first-principles calculations

Monolayer‐Range Compositional Modulations in Al_xGa_1−xN_{(x = 0.6–0.75)} Layers Grown Using Plasma‐Assisted Molecular Beam Epitaxy under Me‐Rich Conditions with an Off‐Centered Spatial Distribution of Activated Nitrogen Flux