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Self-Assembled Local Artificial Substrates of GaAs on Si Substrate.

Bietti S, Somaschini C, Koguchi N, Frigeri C, Sanguinetti S - Nanoscale Res Lett (2010)

Bottom Line: Controlling substrate temperature and amount of supplied gallium is possible to tune the base size of the islands from 70 up to 250 nm and the density from 10(7) to 10(9) cm(-2).The islands show a standard deviation of base size distribution below 10% and their shape evolves changing the aspect ratio from 0.3 to 0.5 as size increases.Due to their characteristics, these islands are suitable to be used as local artificial substrates for the integration of III-V quantum nanostructures directly on silicon substrate.

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ABSTRACT
We propose a self-assembling procedure for the fabrication of GaAs islands by Droplet Epitaxy on silicon substrate. Controlling substrate temperature and amount of supplied gallium is possible to tune the base size of the islands from 70 up to 250 nm and the density from 10(7) to 10(9) cm(-2). The islands show a standard deviation of base size distribution below 10% and their shape evolves changing the aspect ratio from 0.3 to 0.5 as size increases. Due to their characteristics, these islands are suitable to be used as local artificial substrates for the integration of III-V quantum nanostructures directly on silicon substrate.

No MeSH data available.


Related in: MedlinePlus

Left panel: TEM image of a single island on sample E obtained with diffraction vector [220]. Right panel: (220) Bragg spot on diffraction pattern from a single island on sample A
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Figure 2: Left panel: TEM image of a single island on sample E obtained with diffraction vector [220]. Right panel: (220) Bragg spot on diffraction pattern from a single island on sample A

Mentions: Transmission electron microscope measurements confirmed the values obtained by AFM for the island mean base size. Diffraction pattern obtained from TEM measurements allows also to estimate the crystalline quality of the GaAs islands. Images from a single island (right panel in Fig. 2 for sample A) show two different clear Bragg spots for Si and GaAs, demonstrating the formation of single crystal GaAs islands. The two small spots are due to double diffraction from GaAs and Si. Diffraction images obtained with diffraction vector [220] (left panel in Fig. 2 for sample E) evidence Moiré fringes. The spacing between fringes gives a good estimation for distances between planes [220] in Si and GaAs, and the values we obtained are in agreement with the ones expected for bulk material, thus demonstrating fully relaxation of GaAs islands.


Self-Assembled Local Artificial Substrates of GaAs on Si Substrate.

Bietti S, Somaschini C, Koguchi N, Frigeri C, Sanguinetti S - Nanoscale Res Lett (2010)

Left panel: TEM image of a single island on sample E obtained with diffraction vector [220]. Right panel: (220) Bragg spot on diffraction pattern from a single island on sample A
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2991201&req=5

Figure 2: Left panel: TEM image of a single island on sample E obtained with diffraction vector [220]. Right panel: (220) Bragg spot on diffraction pattern from a single island on sample A
Mentions: Transmission electron microscope measurements confirmed the values obtained by AFM for the island mean base size. Diffraction pattern obtained from TEM measurements allows also to estimate the crystalline quality of the GaAs islands. Images from a single island (right panel in Fig. 2 for sample A) show two different clear Bragg spots for Si and GaAs, demonstrating the formation of single crystal GaAs islands. The two small spots are due to double diffraction from GaAs and Si. Diffraction images obtained with diffraction vector [220] (left panel in Fig. 2 for sample E) evidence Moiré fringes. The spacing between fringes gives a good estimation for distances between planes [220] in Si and GaAs, and the values we obtained are in agreement with the ones expected for bulk material, thus demonstrating fully relaxation of GaAs islands.

Bottom Line: Controlling substrate temperature and amount of supplied gallium is possible to tune the base size of the islands from 70 up to 250 nm and the density from 10(7) to 10(9) cm(-2).The islands show a standard deviation of base size distribution below 10% and their shape evolves changing the aspect ratio from 0.3 to 0.5 as size increases.Due to their characteristics, these islands are suitable to be used as local artificial substrates for the integration of III-V quantum nanostructures directly on silicon substrate.

View Article: PubMed Central - HTML - PubMed

ABSTRACT
We propose a self-assembling procedure for the fabrication of GaAs islands by Droplet Epitaxy on silicon substrate. Controlling substrate temperature and amount of supplied gallium is possible to tune the base size of the islands from 70 up to 250 nm and the density from 10(7) to 10(9) cm(-2). The islands show a standard deviation of base size distribution below 10% and their shape evolves changing the aspect ratio from 0.3 to 0.5 as size increases. Due to their characteristics, these islands are suitable to be used as local artificial substrates for the integration of III-V quantum nanostructures directly on silicon substrate.

No MeSH data available.


Related in: MedlinePlus