Growth and motion of liquid alloy droplets of Au on Ge(110)
•When Au is deposited on Ge(110) and heated, liquid AuGe eutectic alloy islands form.•The islands are elongated along[11¯0]. For T> 600 °C, the islands move along [11¯0].•A temperature gradient causes island motion towards hotter temperatures.•The island velocities fit a model of diffusion-driven...
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| Published in: | Ultramicroscopy Vol. 183; pp. 72 - 76 |
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| Main Authors: | , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Netherlands
Elsevier B.V
01-12-2017
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| Online Access: | Get full text |
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| Summary: | •When Au is deposited on Ge(110) and heated, liquid AuGe eutectic alloy islands form.•The islands are elongated along[11¯0]. For T> 600 °C, the islands move along [11¯0].•A temperature gradient causes island motion towards hotter temperatures.•The island velocities fit a model of diffusion-driven motion of a liquid droplet.
The growth of low-dimensional nanostructures of Au on Ge(110) and their temperature-induced motion were observed with Low Energy Electron Microscopy (LEEM). Ge(110) was dosed with 0.5–4 ML of Au and heated to 850 °C. Above 500 °C, liquid AuGe eutectic alloy islands grew on the surface. Islands were 0.3–3.0µm in width, 1–10µm in length, and elongated in the [11¯0] direction. Above 600 °C, islands began moving with speeds of 0.1–1.0µm/s, absorbing smaller stationary islands upon collision and increasing in size to more than 100µm in width. A temperature gradient of ∼0.017 °C/µm across the sample results in a gradient in the Ge concentration across the islands, inducing their movement in the direction of increasing temperature. Optical microscopy confirmed that the large islands moved from the cooler edges of the sample towards its hotter center. The mechanism for motion of the droplets is discussed, and the island velocities fit well to a model for diffusion-driven motion of the liquid droplet. When the temperature was subsequently lowered, islands became supersaturated with Ge, which crystallized on the island edges. |
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| ISSN: | 0304-3991 1879-2723 |
| DOI: | 10.1016/j.ultramic.2017.05.005 |