Atomically flat two-dimensional silicon crystals with versatile electronic properties

Abstract

Silicon (Si) is one of the most extensively studied materials owing to its significance to semiconductor science and technology. While efforts to find a new three-dimensional (3D) Si crystal with unusual properties have made some progress, its two-dimensional (2D) phases have not yet been explored as much. Here, based on a newly developed systematic $ab$ $initio$ materials searching strategy, we report a series of novel 2D Si crystals with unprecedented structural and electronic properties. The new structures exhibit perfectly planar outermost surface layers of a distorted hexagonal network with their thicknesses varying with the atomic arrangement inside. Dramatic changes in electronic properties ranging from semimetal to semiconducting with indirect energy gaps and even to one with direct energy gaps are realized by varying thickness as well as by surface oxidation. Our predicted 2D Si crystals with flat surfaces and tunable electronic properties will shed light on the development of silicon-based 2D electronics technology.

References in corpus (5)

• Two Dimensional Atomic Crystals
• Atomically thin p-n junctions with van der Waals heterointerfaces
• Electronic structure of silicon-based nanostructures
• Structural stability and energy-gap modulation through atomic protrusion in freestanding bilayer silicene
• Structural Evolution and Optoelectronic Applications of Multilayer Silicene

Cited by in corpus (3)

• A new family of two-dimensional crystals: open-framework T${}_3$X (T=C, Si, Ge, Sn; X=O, S, Se, Te) compounds with tetrahedral bonding
• Ab initio quantum transport in AB-stacked bilayer penta-silicene using atomic orbitals
• Promising photovoltaic efficiency of a layered silicon oxide crystal Si${}_3$O