Impact of Rotation Rate on Bismuth Saturation in GaAsBi Grown by Molecular Beam Epitaxy

Stevens, Margaret A.; Grossklaus, Kevin A.; McElearney, John; Vandervelde, Thomas E.

doi:10.1007/s11664-019-06949-6

Cited by 9 publications

(5 citation statements)

References 34 publications

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“…A vertical spiral in regards to Bi concentration can be obtained in GaAsBi this way, as has been well explained in M.A. Stevens et al [66]. A cross-sectional HAADF image of the GaAsBi sample S3 is shown in Fig.…”

Section: Resultssupporting

confidence: 60%

“…f Horizontally summed vertical X-ray counts profile of the raw As-K and Bi-M signal. Two aligned data sets are combined to obtain the profile [66]. In contrast to samples S1 and S2, the VCM is achieved in S3 by utilizing a slower substrate rotation rate (RPM), which is coupled to intrinsically inhomogeneous elemental flux profiles reaching the substrate in a typical MBE chamber.…”

Section: Resultsmentioning

confidence: 99%

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Atomic-Resolution EDX, HAADF, and EELS Study of GaAs1-xBix Alloys

et al. 2020

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The distribution of alloyed atoms in semiconductors often deviates from a random distribution which can have significant effects on the properties of the materials. In this study, scanning transmission electron microscopy techniques are employed to analyze the distribution of Bi in several distinctly MBE grown GaAs 1−x Bi x alloys. Statistical quantification of atomic-resolution HAADF images, as well as numerical simulations, are employed to interpret the contrast from Bi-containing columns at atomically abrupt (001) GaAs-GaAsBi interface and the onset of CuPt-type ordering. Using monochromated EELS mapping, bulk plasmon energy red-shifts are examined in a sample exhibiting phase-separated domains. This suggests a simple method to investigate local GaAsBi unit-cell volume expansions and to complement standard X-ray-based lattice-strain measurements. Also, a single-variant CuPt-ordered GaAsBi sample grown on an offcut substrate is characterized with atomic scale compositional EDX mappings, and the order parameter is estimated. Finally, a GaAsBi alloy with a vertical Bi composition modulation is synthesized using a low substrate rotation rate. Atomically, resolved EDX and HAADF imaging shows that the usual CuPt-type ordering is further modulated along the [001] growth axis with a period of three lattice constants. These distinct GaAsBi samples exemplify the variety of Bi distributions that can be achieved in this alloy, shedding light on the incorporation mechanisms of Bi atoms and ways to further develop Bi-containing III-V semiconductors.

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Section: Resultssupporting

confidence: 60%

Section: Resultsmentioning

confidence: 99%

Atomic-Resolution EDX, HAADF, and EELS Study of GaAs1-xBix Alloys

et al. 2020

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“…Stevens et al made similar observations at 250 °C. [ 123 ] However, it is not yet clear whether this technique can increase the Bi contents accessible at high temperatures, as required for high‐quality device growth. Existing temperature‐limited Bi content predictions are all based on quasiequilibrium growth conditions [ 92,97,104 ] and exceeding these limits through nonequilibrium growth may lead to substantially reduced device dark currents.…”

Section: Prospects For Improving Mbe Growthmentioning

confidence: 99%

GaAsBi: From Molecular Beam Epitaxy Growth to Devices

Richards

Bailey

Liu

et al. 2021

Physica Status Solidi (b)

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GaAsBi has been researched as a candidate material for optoelectronic devices for around two decades. Bi‐induced localized states induce a rapid rising of the valence band edge through a band anticrossing interaction, which has a profound effect on the bandgap and the spin–orbit splitting. The band engineering possible, even with just a few percent bismuth, makes GaAsBi an attractive material for THz emitters, telecommunication lasers, and low noise photodetectors, among other devices. There has been substantial progress in some of these areas; however, progress toward many of the potential applications of GaAsBi has been hindered by device quality issues, brought about by the low substrate temperatures necessary for the growth of GaAsBi with sufficiently large Bi fractions. This review, presents an overview of the applications for which GaAsBi has been advocated and the key results in these areas. The molecular beam epitaxy growth and postgrowth processing of GaAsBi are then explored as well as the novel techniques that have been suggested to improve material quality.

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“…The large size and low electronegativity of Bi have limited the impact of this alloy and introduced many challenges during the epitaxial growth, such as phase separation [9], surface droplets [10,11], atomic ordering [12][13][14]. To promote the Bi incorporation, the alloy needs to be grown using comparatively lower temperatures, and modified V/III flux ratios [3,[15][16][17][18][19][20][21][22][23][24][25]. By growing at 200 • C using MBE, Lewis et al reported the record high Bi concentration at 22% [20].…”

Section: Introductionmentioning

confidence: 99%

GaAsPBi epitaxial layer grown by molecular beam epitaxy

Himwas¹,

Soison²,

Kijamnajsuk³

et al. 2020

Semicond. Sci. Technol.

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GaAsPBi is a new class of quaternary III-V compounds that extends the concept of band gap engineering on GaAs with potentials for lattice matching and excellent temperature stability. The alloy has so far been grown only by metalorganic vapor phase epitaxy and this work represents the first epitaxial results of the alloy grown by molecular beam epitaxy (MBE), an alternative technique and better suited for low-temperature processes involving Bismuth. Crystalline quality of the alloys is probed by high-resolution x-ray diffraction and photoluminescence (PL) which show that smooth and optically active films can be grown in limited parameter windows. Temperature-dependent PL shows that the 200 nm, MBE-grown GaAs 0.38 P 0.44 Bi 0.18 film (the composition estimated using x-ray photoelectron spectroscopy) has a band gap temperature stability close to that of GaAsBi, and superior to GaAs. The role of Bi in the quaternary alloy is complicated: Bi not only gets incorporated into the growing film but also enhances the P molar fraction. Based on this insight, strategies for growing GaAsPBi epilayers which are lattice-matched to GaAs are described, potentially affecting many important III-V based heterostructures such as lasers, light-emitting diodes, and solar cells.

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Impact of Rotation Rate on Bismuth Saturation in GaAsBi Grown by Molecular Beam Epitaxy

Cited by 9 publications

References 34 publications

Atomic-Resolution EDX, HAADF, and EELS Study of GaAs1-xBix Alloys

Atomic-Resolution EDX, HAADF, and EELS Study of GaAs1-xBix Alloys

GaAsBi: From Molecular Beam Epitaxy Growth to Devices

GaAsPBi epitaxial layer grown by molecular beam epitaxy

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