Metal Sheet of Atomic Thickness Embedded in Silicon.

Bondarenko, Leonid V; Tupchaya, Alexandra Y; Vekovshinin, Yurii E; Gruznev, Dimitry V; Mihalyuk, Alexey N; Olyanich, Dmitry A; Ivanov, Yurii P; Matetskiy, Andrey V et al. · ACS Nano · 2021

basic_science · Level V

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Abstract

The controlled confinement of the metallic delta-layer to a single atomic plane has so far remained an unsolved problem. In the present study, the delta-type structure with atomic sheet of NiSi<sub>2</sub> silicide embedded into a crystalline Si matrix has been fabricated using room-temperature overgrowth of a Si film onto the Tl/NiSi<sub>2</sub>/Si(111) atomic sandwich in ultrahigh vacuum. Tl atoms segregate at the growing Si film surface, and the 1.5-3.0 nm thick epitaxially crystalline Si layer forms atop the NiSi<sub>2</sub> sheet. Confinement of the NiSi<sub>2</sub> layer to a single atomic plane has been directly confirmed by transmission electron microscopy. The NiSi<sub>2</sub> delta-layer demonstrates a <i>p</i>-type conductivity associated with the electronic transport through the two hole-like and one electron-like interface-state bands. The basic structural and electronic properties of the NiSi<sub>2</sub> delta-layer remain after keeping the sample in air for one year.