Ternary AlGaN Alloys with High Al Content and Enhanced Compositional Homogeneity Grown by Plasma-Assisted Molecular Beam Epitaxy

Fellmann, V.; Jaffrennou, P.; Sam-Giao, Diane; Gayral, B.; Lorenz, K.; Alves, E.; Daudin, B.

doi:10.1143/jjap.50.031001

Cited by 12 publications

(11 citation statements)

References 48 publications

(56 reference statements)

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“…This behavior seems to indicate that the growth mechanisms of strained nanometer thick layers are influenced by the alloy Al composition, considering that the same growth conditions (growth rates, III / V ratio and temperature) have been used to fabricate the samples. Actually, it has been reported that thick AlxGa1-xN layers grown by plasma assisted MBE present composition fluctuations for growth temperatures above 670°C, 47 and for Al composition of 50% or below. 48 Indeed, such growth temperatures and Al compositions correspond to the ones used for the fabrication of the AlyGa1-yN QDs.…”

Section: Pl Radiative Efficiency and Iqementioning

confidence: 99%

Internal quantum efficiencies of AlGaN quantum dots grown by molecular beam epitaxy and emitting in the UVA to UVC ranges

Brault

Matta

Ngo

et al. 2019

Journal of Applied Physics

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AlyGa1-yN quantum dots (QDs) have been grown by molecular beam epitaxy on AlxGa1-xN (0001) using a 2 dimensional -3 dimensional growth mode transition that leads to the formation of QDs. QDs have been grown for Al compositions y varying between 10% and 40%. The influence the active region design (composition y, QD height and band gap difference (ΔEg) between the AlxGa1-xN cladding layer and the AlyGa1-yN QDs) is discussed based on microscopy, continuous wave photoluminescence (PL) and time-resolved PL (TRPL) measurements. In particular, increasing y leads to a shift of the QD emission towards shorter wavelengths, allowing covering a spectral range in the UV from 332 nm (UVA) to 276 nm (UVC) at room temperature (RT). The low temperature (LT)

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Section: Pl Radiative Efficiency and Iqementioning

confidence: 99%

Internal quantum efficiencies of AlGaN quantum dots grown by molecular beam epitaxy and emitting in the UVA to UVC ranges

Brault

Matta

Ngo

et al. 2019

Journal of Applied Physics

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“…Recently, Fellmann et al 36 considered the growth kinetics of Al x Ga 1 − x N ( x ∼ 0.5–0.6) under different stoichiometric conditions and substrate temperatures varying from 540 to 760 °C. They reported that the unity flux ratio ( F III / F N ∼ 1) and rather low growth temperatures of 650–680 °C limiting the diffusion of Ga adatoms are the preferable growth conditions in order to improve the structural quality of Al x Ga 1 − x N ( x ∼ 0.5) layers.…”

Section: Introductionmentioning

confidence: 99%

Plasma‐assisted molecular beam epitaxy of AlGaN heterostructures for deep‐ultraviolet optically pumped lasers

Jmerik

Луценко

Иванов

2013

Physica Status Solidi (a)

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The paper reports on elaboration of plasma-assisted molecular beam epitaxy (MBE) of Al x Ga 1 À x N-based quantum-well (QW) structures with high Al content (up to 50% in the QW) grown directly on c-sapphire. Different elements of the structure design are considered consecutively in detail along with the advanced growth approaches developed for each element. Special attention is paid to the growth conditions of (i) AlN nucleation layers with suppressed generation of threading dislocations (TDs), (ii) 2-mm thick AlN buffer layers with atomically smooth droplet-free morphology (rms ¼ 0.46 nm) grown under the strongly metal-rich conditions, (iii) cladding and waveguide AlGaN layers also possessing the atomically smooth droplet-free morphology that is ensured by the accurately established phase diagram of metal(Ga)-rich growth conditions within the temperature range 660-780 8C. Employing several 3-nm thick strained GaN insertions in the AlN buffer layer and a AlGaN/AlN superlattice (SL) on top of it is shown to result in a significant decrease of TD's density down to 10 8 -10 9 cm À2 in the top QW region fabricated by a submonolayer digital alloying (SDA) technique. Finally, advanced AlGaN-based QW structures are presented, which demonstrate optically pumped lasing within the deep-ultraviolet (UV) wavelength range with the threshold power density below 600 kW cm À2 (at 289 nm).

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“…(d)-(f)). An insignificant band filling effect is due to a reduced alloy broadening effect in AlGaN under optimized growth kinetics [37,38]. The blue-shift behavior, however, does occur in AlGaN quantum well based planar devices in the presence of high polarization fields [39].…”

Section: Resultsmentioning

confidence: 99%

Ultraviolet-A LED Based on Quantum-Disks-in-AlGaN-Nanowires—Optimization and Device Reliability

Janjua

Priante

Prabaswara

et al. 2018

2018 IEEE Photonics Conference (IPC)

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Group-III nitride-based ultraviolet (UV) quantum-disks (Qdisks) nanowires (NWs) light-emitting diodes grown on silicon substrates offer a scalable, environment-friendly, compact, and low-cost solution for numerous applications in solid-state lighting, spectroscopy, and biomedical. However, the internal quantum efficiency, injection efficiency, and extraction efficiency need to be further improved. The focus of this paper encompasses investigations based on structural optimization, device simulation, and device reliability. To optimize a UV-A (320-400 nm) device structure we utilize the self-assembled quantum-disk-NWs with varying quantum-disks thickness to study carrier separation in active-region and implement an improved p-contact-layer to increase output power. By simulation, we found a 100× improvement in the direct recombination rate for samples with thicker Qdisks thickness of ~5 monolayers (MLs) compared to the sample with ~2 MLs-thick Qdisks. Moreover, the sample with graded top Mg-doped AlGaN layer in conjunction with thin Mg-doped GaN layer shows 10× improvement in the output power compared to the samples with thicker top Mg-doped GaN absorbing contact layer. A fitting with ABC model revealed the increase in non-radiative recombination centers in the active region after a soft stress-test. This work aims to shed light on the research efforts required for furthering the UV NWs LED research for practical applications.

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Ternary AlGaN Alloys with High Al Content and Enhanced Compositional Homogeneity Grown by Plasma-Assisted Molecular Beam Epitaxy

Cited by 12 publications

References 48 publications

Internal quantum efficiencies of AlGaN quantum dots grown by molecular beam epitaxy and emitting in the UVA to UVC ranges

Internal quantum efficiencies of AlGaN quantum dots grown by molecular beam epitaxy and emitting in the UVA to UVC ranges

Plasma‐assisted molecular beam epitaxy of AlGaN heterostructures for deep‐ultraviolet optically pumped lasers

Ultraviolet-A LED Based on Quantum-Disks-in-AlGaN-Nanowires—Optimization and Device Reliability

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