Nucleation of Ga droplets self-assembly on GaAs(111)A substrates

Tuktamyshev, Artur; Fedorov, Alexey; Bietti, Sergio; Vichi, Stefano; Tambone, Riccardo; Tsukamoto, Shiro; Sanguinetti, S.

doi:10.1038/s41598-021-86339-3

Cited by 7 publications

(4 citation statements)

References 45 publications

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“…This suggests that the adatom diffusion length for this sample is similar to the terrace width (arising from the local substrate offcut), corresponding to an adatom diffusion length of 250-500 nm. This is somewhat larger than the Ga diffusion lengths quoted in literature for GaAs(111)A MBE growth, which range from 100 nm to several hundred nanometres [34][35][36]. Furthermore, for the sample grown under 0.86 ML s −1 Bi, the complete absence of any islands on the surface indicates that the diffusion length of Ga for this sample is significantly greater than the terrace width of up to 300 nm.…”

Section: Bi:gaas(111)a Mbecontrasting

confidence: 52%

Bismuth surfactant-enhanced III-As epitaxy on GaAs(111)A

Hassanen

Herránz

Geelhaar

et al. 2023

Semicond. Sci. Technol.

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Quantum dot (QD) growth on high (c3v) symmetry GaAs{111}surfaces holds promise for efficient entangled photon sources. Unfortunately,homoepitaxy on GaAs{111} surfaces suffers from surface roughness/defectsand InAs deposition does not natively support Stranski–Krastanov (SK) QDgrowth. Surfactants have been identified as effective tools to alter the epitaxialgrowth process of III-V materials, however, their use remains unexplored onGaAs{111}. Here, we investigate Bi as a surfactant in III-As molecular beamepitaxy (MBE) on GaAs(111)A substrates, demonstrating that Bi can eliminatesurface defects/hillocks in GaAs and (Al,Ga)As layers, yielding atomically-smoothhillock-free surfaces with RMS roughness values as low as 0.13 nm. Increasing Bifluxes are found to result in smoother surfaces and Bi is observed to increaseadatom diffusion. The Bi surfactant is also shown to trigger a morphologicaltransition in InAs/GaAs(111)A films, directing the 2D InAs layer to rearrange into3D nanostructures, which are promising candidates for high-symmetry quantumdots. The desorption activation energy (UDes) of Bi on GaAs(111)A was measuredby reflection high energy electron diffraction (RHEED), yielding UDes = 1.7 ±0.4 eV. These results illustrate the potential of Bi surfactants on GaAs(111)A andwill help pave the way for GaAs(111)A as a platform for technological applicationsincluding quantum photonics.

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Section: Bi:gaas(111)a Mbecontrasting

confidence: 52%

Bismuth surfactant-enhanced III-As epitaxy on GaAs(111)A

Hassanen

Herránz

Geelhaar

et al. 2023

Semicond. Sci. Technol.

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“…The XPS modeling of GaAs with Ga-rich termination has already been studied in ref . The surface XPS ratio Ga 3d/As 3d of 0.77 shows a 1.5 ML-thick Ga-rich surface, consistent with the (2 × 2) Ga-rich surface reconstruction. , …”

Section: Experimental Methodsmentioning

confidence: 67%

Growth Mechanisms of GaN/GaAs Nanostructures by Droplet Epitaxy Explained by Complementary Experiments and Simulations

Tsamo,

Nastovjak,

Shwartz

et al. 2024

J. Phys. Chem. C

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In this work, we present the conception and study of gallium nitride (GaN) nanostructures on a gallium arsenide (GaAs) substrate with (111)A orientation. The nanostructures were designed by GaN droplet epitaxy and studied in situ by X-ray photoelectron spectroscopy and ex situ by atomic force microscopy, scanning electron microscopy, and transmission electron microscopy. These studies were coupled with kinetic Monte Carlo simulations to precisely understand the phenomena occurring during the nitridation and to find the optimum conditions for complete nitridation of gallium droplets. The HRTEM observation showed a cubic (zinc blende) crystal structure of the GaN nanodots for a nitridation at 300 °C. Ramping the temperature from 100 to 350 °C during droplet nitridation enabled to obtain a very high density (>10 11 cm −2 ) of GaN nanodots with the zinc blende crystallinity.

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“…More in details, the droplet density is affected by substrate temperature and Ga flux, while the droplet volume is mostly affected by the Ga amount. 18,23 Then the Ga droplets were exposed to an As beam equivalent pressure of 5.10-5 torr at 150°C for 3 min to crystallize into GaAs. During the crystallization step, the size and morphology of the QDs can be controlled by changing substrate temperature and As pressure.…”

Section: Methodsmentioning

confidence: 99%

Optically controlled dual-band quantum dot infrared photodetector

Vichi

Bietti

Basset

et al. 2022

Nanomaterials and Nanotechnology

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We present the design for a novel type of dual-band photodetector in the thermal infrared spectral range, the Optically Controlled Dual-band quantum dot Infrared Photodetector (OCDIP). This concept is based on a quantum dot ensemble with a unimodal size distribution, whose absorption spectrum can be controlled by optically injected carriers. An external pumping laser varies the electron density in the QDs, permitting to control the available electronic transitions and thus the absorption spectrum. We grew a test sample which we studied by AFM and photoluminescence. Based on the experimental data, we simulated the infrared absorption spectrum of the sample, which showed two absorption bands at 5.85 μm and 8.98 μm depending on the excitation power.

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Nucleation of Ga droplets self-assembly on GaAs(111)A substrates

Cited by 7 publications

References 45 publications

Bismuth surfactant-enhanced III-As epitaxy on GaAs(111)A

Bismuth surfactant-enhanced III-As epitaxy on GaAs(111)A

Growth Mechanisms of GaN/GaAs Nanostructures by Droplet Epitaxy Explained by Complementary Experiments and Simulations

Optically controlled dual-band quantum dot infrared photodetector

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