[2E09-15] Two-Dimensional Materials 

3:15 PM - 3:30 PM JST(6:15 AM - 6:30 AM UTC)

[2E11] Ge segregation pathway for selective formation of monolayer germanene on Ag(111)/Ge(111)

*Tomoo Terasawa^1,2, Daiki Katsube³, Masahiro Yano¹, Takahiro Ozawa², Yasutaka Tsuda⁴, Akitaka Yoshigoe⁴, Hidehito Asaoka¹, Seiya Suzuki¹ (1. Advanced Science Research Center, Japan Atomic Energy Agency (Japan), 2. Institute of Industrial Science, The University of Tokyo (Japan), 3. Japan Fine Ceramics Center (Japan), 4. Materials Sciences Research Center, Japan Atomic Energy Agency (Japan))

Ge segregation through Ag(111) thin films on Ge(111) yields monolayer germanene after annealing at 500 °C and cooling to room temperature; however, why germanene is selected over Ge byproducts remains unclear. We used in situ Raman and X-ray photoelectron spectroscopies under vacuum to track Ge-Ge bonding and the surface Ge amount during annealing and cooling. Heating to around 300 °C produced 3D Ge islands, whereas cooling from 500 to 300 °C increased the surface Ge amount to the monolayer range and produced germanene. We analyzed the temperature-dependent Ge solubility and diffusion length in Ag, which were revealed to govern the Ge segregation and germanene formation. This provides conditions for selective formation of germanene by segregation and a basis for forming metastable two-dimensional materials under vacuum.

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