Epitaxial phases of high Bi content GaSbBi alloys

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Epitaxial phases of high Bi content GaSbBi alloys. / Hilska, Joonas ; Koivusalo, Eero ; Puustinen, Janne; Suomalainen, Soile; Guina, Mircea.

In: Journal of Crystal Growth, Vol. 516, 15.06.2019, p. 67-71.

Research output: Contribution to journal › Article › Scientific › peer-review

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@article{5eee811b271249849b98e156710129be,

title = "Epitaxial phases of high Bi content GaSbBi alloys",

abstract = "GaSbBi alloys have recently emerged as attractive materials for mid-infrared optoelectronics owing to strong band gap reduction enabled by Bi incorporation into the GaSb matrix. The fundamental understanding of the epitaxial process required to demonstrate high quality crystals is in an early-developmental phase. From this perspective, we report on the key role played by the Sb/Ga flux ratio in controlling the structural quality and incorporation of high Bi content GaSbBi (up to 14.5{\%}-Bi), revealing three distinct epitaxial phases. The first phase (below stoichiometric Sb/Ga) exhibits Ga-Bi compound droplets, low crystal quality, and reduced Bi content. At the second phase (above stoichiometric Sb/Ga), the crystal exhibits smooth surfaces and excellent crystallinity with efficient Bi incorporation. The last phase corresponds to exceeding a Sb/Ga threshold that leads to reduced Bi incorporation, Bi droplets and degraded crystallinity. This threshold value that defines the optimal growth window is controlled by the temperature as well as the Bi/Ga ratio. Increasing temperature increases the threshold, albeit simultaneously reducing Bi incorporation. Conversely, increasing the Bi/Ga flux ratio increases Bi incorporation, while narrowing down and ultimately closing the window. This study provides a general framework enabling development of high quality GaSbBi heterostructures for emerging mid-infrared optoelectronics.",

keywords = "A3. Molecular beam epitaxy, B1. Antimonides, B1. Bismuth compounds, B2. Semiconducting III-V materials, B2. Semiconducting ternary compounds",

author = "Joonas Hilska and Eero Koivusalo and Janne Puustinen and Soile Suomalainen and Mircea Guina",

year = "2019",

month = "6",

day = "15",

doi = "10.1016/j.jcrysgro.2019.03.028",

language = "English",

volume = "516",

pages = "67--71",

journal = "Journal of Crystal Growth",

issn = "0022-0248",

publisher = "Elsevier",

}

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TY - JOUR

T1 - Epitaxial phases of high Bi content GaSbBi alloys

AU - Hilska, Joonas

AU - Koivusalo, Eero

AU - Puustinen, Janne

AU - Suomalainen, Soile

AU - Guina, Mircea

PY - 2019/6/15

Y1 - 2019/6/15

N2 - GaSbBi alloys have recently emerged as attractive materials for mid-infrared optoelectronics owing to strong band gap reduction enabled by Bi incorporation into the GaSb matrix. The fundamental understanding of the epitaxial process required to demonstrate high quality crystals is in an early-developmental phase. From this perspective, we report on the key role played by the Sb/Ga flux ratio in controlling the structural quality and incorporation of high Bi content GaSbBi (up to 14.5%-Bi), revealing three distinct epitaxial phases. The first phase (below stoichiometric Sb/Ga) exhibits Ga-Bi compound droplets, low crystal quality, and reduced Bi content. At the second phase (above stoichiometric Sb/Ga), the crystal exhibits smooth surfaces and excellent crystallinity with efficient Bi incorporation. The last phase corresponds to exceeding a Sb/Ga threshold that leads to reduced Bi incorporation, Bi droplets and degraded crystallinity. This threshold value that defines the optimal growth window is controlled by the temperature as well as the Bi/Ga ratio. Increasing temperature increases the threshold, albeit simultaneously reducing Bi incorporation. Conversely, increasing the Bi/Ga flux ratio increases Bi incorporation, while narrowing down and ultimately closing the window. This study provides a general framework enabling development of high quality GaSbBi heterostructures for emerging mid-infrared optoelectronics.

AB - GaSbBi alloys have recently emerged as attractive materials for mid-infrared optoelectronics owing to strong band gap reduction enabled by Bi incorporation into the GaSb matrix. The fundamental understanding of the epitaxial process required to demonstrate high quality crystals is in an early-developmental phase. From this perspective, we report on the key role played by the Sb/Ga flux ratio in controlling the structural quality and incorporation of high Bi content GaSbBi (up to 14.5%-Bi), revealing three distinct epitaxial phases. The first phase (below stoichiometric Sb/Ga) exhibits Ga-Bi compound droplets, low crystal quality, and reduced Bi content. At the second phase (above stoichiometric Sb/Ga), the crystal exhibits smooth surfaces and excellent crystallinity with efficient Bi incorporation. The last phase corresponds to exceeding a Sb/Ga threshold that leads to reduced Bi incorporation, Bi droplets and degraded crystallinity. This threshold value that defines the optimal growth window is controlled by the temperature as well as the Bi/Ga ratio. Increasing temperature increases the threshold, albeit simultaneously reducing Bi incorporation. Conversely, increasing the Bi/Ga flux ratio increases Bi incorporation, while narrowing down and ultimately closing the window. This study provides a general framework enabling development of high quality GaSbBi heterostructures for emerging mid-infrared optoelectronics.

KW - A3. Molecular beam epitaxy

KW - B1. Antimonides

KW - B1. Bismuth compounds

KW - B2. Semiconducting III-V materials

KW - B2. Semiconducting ternary compounds

U2 - 10.1016/j.jcrysgro.2019.03.028

DO - 10.1016/j.jcrysgro.2019.03.028

M3 - Article

VL - 516

SP - 67

EP - 71

JO - Journal of Crystal Growth

JF - Journal of Crystal Growth

SN - 0022-0248

ER -

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