Observation of columnar microstructure in lattice-matched InAlN/GaN grown by plasma assisted molecular beam epitaxy

Choi, Sunghee; Wu, Feng; Shivaraman, Ravi; Young, Erin C.; Speck, James S.

doi:10.1063/1.4725482

Cited by 46 publications

(45 citation statements)

References 12 publications

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“…It is worth noting that APT analysis of the stoichiometry of Table 1. Relaxed lattice parameters of the binaries AlN [42] and InN [43] and stiffness coefficients [43,44] III-nitride materials is significantly dependent on the parameters used in the APT experiment for reasons which are still under debate [35,[49][50][51][52]. Nevertheless, for the analysis of both In 1-y Ga y N and Al 1−x In x N, the measured fraction of metallic sites occupied by In atoms has been found to be relatively stable to the running conditions [53].…”

Section: Compositional Analysismentioning

confidence: 99%

Validity of Vegard’s rule for Al_1−xIn_xN (0.08 < x < 0.28) thin films grown on GaN templates

Magalhães

Franco

Watson

et al. 2017

J. Phys. D: Appl. Phys.

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Section: Compositional Analysismentioning

confidence: 99%

Validity of Vegard’s rule for Al_1−xIn_xN (0.08 < x < 0.28) thin films grown on GaN templates

Magalhães

Franco

Watson

et al. 2017

J. Phys. D: Appl. Phys.

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“…Due to large differences in binding energies between Al-N (2.88 eV) and In-N (1.98 eV) bonds, InAlN/GaN heterostructures, especially those grown by molecular beam epitaxy, generally exhibit severe lateral compositional inhomogeneity. [5][6][7] In compositionally inhomogeneous InAlN layers, alternate AlN-rich and InNrich regions form columnar clusters with widths about 10 nm. 5,8 Alloy clustering causes 2DEG subband energy fluctuations and InAlN conduction band fluctuations (see Figure 1), both affects the electron transport properties of InAlN/GaN heterostructures.…”

Section: Introductionmentioning

confidence: 99%

Conduction band fluctuation scattering due to alloy clustering in barrier layers in InAlN/GaN heterostructures

Chen

Chong³

2017

AIP Advances

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In InAlN/GaN heterostructures, alloy clustering-induced InAlN conduction band fluctuations interact with electrons penetrating into the barrier layers and thus affect the electron transport. Based on the statistical description of InAlN compositional distribution, a theoretical model of the conduction band fluctuation scattering (CBFS) is presented. The model calculations show that the CBFS-limited mobility decreases with increasing two-dimensional electron gas sheet density and is inversely proportional to the squared standard deviation of In distribution. The AlN interfacial layer can effectively suppress the CBFS via decreasing the penetration probability. This model is directed towards understanding the transport properties in heterostructure materials with columnar clusters.

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“…al. [3], InAlN layers were grown on commercial (0001) Ga-face Lumilog GaN templates by plasma assisted molecular beam epitaxy. The InAlN layer was grown on a GaN-buffer at 480 C under N-APT.…”

mentioning

confidence: 99%

Atom Probe Tomography of III-Nitrides Based Semiconducting Devices

Shivaraman¹,

Wu²,

Choi³

et al. 2013

Microsc Microanal

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Commercial Light emitting devices are grown on c-plane Gallium Nitride. The active region -where the photons are generated -is an Indium Gallium Nitride quantum well (QW). The radiative recombination efficiency of these light emitters is related to the carrier charge density distribution and transport across and within this active region. The charge density and charge transport in the device is governed by the potential landscape that charges move through. This potential landscape is intimately related to the Indium distribution in inside the quantum well. For instance, higher indium regions experience larger strain and hence greater piezoelectric field contribution and also a greater electrostatic potential, leading to deeper troughs in the energy landscape. Atom probe tomography (APT) emerges as an ideal characterization tool to map this 3-D Indium distribution. APT combines time-of-flight measurement with point projection imaging [1]. The APT analysis of the c-plane GaN/InGaN LED was performed using the Cameca Local Electrode Atom Probe 3000XHR. The epi-structure of the LED for APT analysis was obtained from Walsin Lihwa Corp. It consisted of 9 pairs of QW/quantum barrier (QB) structures, where the barrier thickness was around 10 nm and well thickness around 2.5 nm. The reconstructed APT data which delineates the LED heterostructure is shown in Figure 1(a). The average quantum well III-site Indium concentration was estimated to be ~16%. The barrier/quantum well interfaces are not abrupt as can be seen in Figure 1(b). There is an asymmetry in the chemical diffusivity at the upper and lower interfaces -the upper interface being more chemically diffuse. A difference plot between experimentally observed and simulated binomial bin distributions reveals that the Indium distribution is random (Figure 1(c)).These indium composition maps obtained from APT experiments were employed to generate the potential landscape in device simulations. Recently, in their work on 2-D LED device modeling, Wu et. al.[2] assumed an Indium distribution where the lateral variations were assumed sinusoidal and the composition variations in the growth direction were characterized by a Gaussian. Their result ( Figure 1(d)) showed s in the QW, the low forward voltage in the commercial blue LED diode can be explained be ignored in the device design and modeling.Another technologically promising ternary III-nitride material system is InAlN -a promising candidate for both optoelectronic and electronic devices. InAlN with 18% In concentration has comparable a-axis lattice constant to GaN, which makes it possible to grow lattice-matched (0001) structures. In the work by Choi et. al. [3], InAlN layers were grown on commercial (0001) Ga-face Lumilog GaN templates by plasma assisted molecular beam epitaxy. The InAlN layer was grown on a GaN-buffer at 480 C under N-APT. Figure 956

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Observation of columnar microstructure in lattice-matched InAlN/GaN grown by plasma assisted molecular beam epitaxy

Cited by 46 publications

References 12 publications

Validity of Vegard’s rule for Al_1−xIn_xN (0.08 < x < 0.28) thin films grown on GaN templates

Validity of Vegard’s rule for Al_1−xIn_xN (0.08 < x < 0.28) thin films grown on GaN templates

Conduction band fluctuation scattering due to alloy clustering in barrier layers in InAlN/GaN heterostructures

Atom Probe Tomography of III-Nitrides Based Semiconducting Devices

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Observation of columnar microstructure in lattice-matched InAlN/GaN grown by plasma assisted molecular beam epitaxy

Cited by 46 publications

References 12 publications

Validity of Vegard’s rule for Al1−xInxN (0.08 < x < 0.28) thin films grown on GaN templates

Validity of Vegard’s rule for Al1−xInxN (0.08 < x < 0.28) thin films grown on GaN templates

Conduction band fluctuation scattering due to alloy clustering in barrier layers in InAlN/GaN heterostructures

Atom Probe Tomography of III-Nitrides Based Semiconducting Devices

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Validity of Vegard’s rule for Al_1−xIn_xN (0.08 < x < 0.28) thin films grown on GaN templates

Validity of Vegard’s rule for Al_1−xIn_xN (0.08 < x < 0.28) thin films grown on GaN templates