Spontaneous formation of nanostructures by surface spinodal decomposition in GaAs1-xBix epilayers

E. Luna; M. Wu; J. Puustinen; M. Guina; A. Trampert

doi:10.1063/1.4919896

Spontaneous formation of nanostructures by surface spinodal decomposition in GaAs1-xBix epilayers

E. Luna^*
, M. Wu
, J. Puustinen
, M. Guina
, A. Trampert

^*Corresponding author for this work

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

30 Citations (Scopus)

Abstract

We report on the spontaneous formation of lateral composition modulations (LCMs) in Ga(As, Bi) epilayers grown by low-temperature (<300 degrees C) molecular beam epitaxy (MBE) on GaAs(001). Both cross-section and plan-view transmission electron microscopy techniques are used to investigate the nature of the LCMs, consisting of Bi-rich cylinder-like nanostructures lying along the [001] growth direction. The observed LCMs are the consequence of a two-dimensional phase separation process occurring at the surface of the growing epilayers, and their columnar nature is consistent with a surface-directed spinodal decomposition process. Although LCMs are thermodynamically driven, we show how they can be kinetically controlled, in particular, through the As/Ga flux ratio and the substrate temperature. This is a result of LCMs developing from surface atomic diffusion processes, since the atomic dimer configurations on the surface alter adatom diffusivity. The significant role of the surface reconstructions is also discussed. (c) 2015 AIP Publishing LLC.

Original language	English
Article number	185302
Number of pages	5
Journal	Journal of Applied Physics
Volume	117
Issue number	18
DOIs	https://doi.org/10.1063/1.4919896
Publication status	Published - 14 May 2015
Publication type	A1 Journal article-refereed

Funding

The authors acknowledge the financial support from the COST Action MP0805. J.P. and M.G. acknowledge the financial support from the Academy of Finland via the HIGHMAT Project (Ref. No. 259111). The authors thank Joonas Hilska for help in sample growth and Doreen Steffen and Astrid Pfeiffer for technical assistance with TEM. The authors acknowledge Ryan B. Lewis for critical reading of the manuscript and fruitful discussions. Finally, we would like to thank M. Masnadi-Shirazi for allowing us to use his experimental data for this study.

Keywords

PHASE-SEPARATION
SEMICONDUCTOR ALLOYS
GROWTH
IN1-XGAXASYP1-Y
DIFFUSION
EPITAXY
GAAS

Publication forum classification

Publication forum level 1

ASJC Scopus subject areas

General Physics and Astronomy

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10.1063/1.4919896

Cite this

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title = "Spontaneous formation of nanostructures by surface spinodal decomposition in GaAs1-xBix epilayers",

abstract = "We report on the spontaneous formation of lateral composition modulations (LCMs) in Ga(As, Bi) epilayers grown by low-temperature (<300 degrees C) molecular beam epitaxy (MBE) on GaAs(001). Both cross-section and plan-view transmission electron microscopy techniques are used to investigate the nature of the LCMs, consisting of Bi-rich cylinder-like nanostructures lying along the [001] growth direction. The observed LCMs are the consequence of a two-dimensional phase separation process occurring at the surface of the growing epilayers, and their columnar nature is consistent with a surface-directed spinodal decomposition process. Although LCMs are thermodynamically driven, we show how they can be kinetically controlled, in particular, through the As/Ga flux ratio and the substrate temperature. This is a result of LCMs developing from surface atomic diffusion processes, since the atomic dimer configurations on the surface alter adatom diffusivity. The significant role of the surface reconstructions is also discussed. (c) 2015 AIP Publishing LLC.",

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AU - Wu, M.

AU - Puustinen, J.

AU - Guina, M.

AU - Trampert, A.

N1 - publication_forum:59616 EXT="Wu, M."

PY - 2015/5/14

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N2 - We report on the spontaneous formation of lateral composition modulations (LCMs) in Ga(As, Bi) epilayers grown by low-temperature (<300 degrees C) molecular beam epitaxy (MBE) on GaAs(001). Both cross-section and plan-view transmission electron microscopy techniques are used to investigate the nature of the LCMs, consisting of Bi-rich cylinder-like nanostructures lying along the [001] growth direction. The observed LCMs are the consequence of a two-dimensional phase separation process occurring at the surface of the growing epilayers, and their columnar nature is consistent with a surface-directed spinodal decomposition process. Although LCMs are thermodynamically driven, we show how they can be kinetically controlled, in particular, through the As/Ga flux ratio and the substrate temperature. This is a result of LCMs developing from surface atomic diffusion processes, since the atomic dimer configurations on the surface alter adatom diffusivity. The significant role of the surface reconstructions is also discussed. (c) 2015 AIP Publishing LLC.

AB - We report on the spontaneous formation of lateral composition modulations (LCMs) in Ga(As, Bi) epilayers grown by low-temperature (<300 degrees C) molecular beam epitaxy (MBE) on GaAs(001). Both cross-section and plan-view transmission electron microscopy techniques are used to investigate the nature of the LCMs, consisting of Bi-rich cylinder-like nanostructures lying along the [001] growth direction. The observed LCMs are the consequence of a two-dimensional phase separation process occurring at the surface of the growing epilayers, and their columnar nature is consistent with a surface-directed spinodal decomposition process. Although LCMs are thermodynamically driven, we show how they can be kinetically controlled, in particular, through the As/Ga flux ratio and the substrate temperature. This is a result of LCMs developing from surface atomic diffusion processes, since the atomic dimer configurations on the surface alter adatom diffusivity. The significant role of the surface reconstructions is also discussed. (c) 2015 AIP Publishing LLC.

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KW - SEMICONDUCTOR ALLOYS

KW - GROWTH

KW - IN1-XGAXASYP1-Y

KW - DIFFUSION

KW - EPITAXY

KW - GAAS

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DO - 10.1063/1.4919896

M3 - Article

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VL - 117

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JF - Journal of Applied Physics

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ER -

Spontaneous formation of nanostructures by surface spinodal decomposition in GaAs1-xBix epilayers

Abstract

Funding

Keywords

Publication forum classification

ASJC Scopus subject areas

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