Epitaxial growth of atomically thin Ga2Se2 films on c-plane sapphire substrates

Abstract

Broadening the variety of two-dimensional (2D) materials and improving the synthesis of ultrathin films are crucial to the development of the semiconductor industry. As a state-of-the-art 2D material, Ga2Se2 has attractive optoelectronic properties when it reaches the atomically-thin regime. However, its van der Waals epitaxial growth, especially for the atomically-thin films, has seldom been studied. In this paper, we used molecular beam epitaxy to synthesize Ga2Se2 single-crystal films with a surface roughness down to 1.82 nm on c-plane sapphire substrates by optimizing substrate temperature, Se:Ga flux ratio, and growth rate. Then we used a 3-step mode to grow Ga2Se2 films with a thickness as low as 3 tetralayers and a surface roughness as low as 0.61 nm, far exceeding the performance of direct growth. Finally, we found that the surface morphology strongly depends on the Se:Ga flux ratio, and higher growth rates widened the suitable flux ratio window for growing Ga2Se2. Overall, this work advances the understanding of the vdW epitaxy growth mechanism for post-transition metal monochalcogenides on sapphire substrates.

References in corpus (9)

• Electric Field Effect in Atomically Thin Carbon Films
• Ultrafast Charge Transfer in Atomically Thin MoS2/WS2 Heterostructures
• Tunable Magnetism and Half-Metallicity in Hole-doped Monolayer GaSe
• Epitaxial growth of topological insulator Bi2Se3 film on Si(111) with atomically sharp interface
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• Solution-processed GaSe nanoflake-based films for photoelectrochemical water splitting and photoelectrochemical-type photodetectors
• Structural phase transitions between layered Indium Selenide for inte-grated photonic memory
• Optimization of the growth of the van der Waals materials Bi2Se3 and (Bi0.5In0.5)2Se3 by molecular beam epitaxy
• Epitaxial growth of atomically thin Ga2Se2 films on c-plane sapphire substrates

Cited by in corpus (5)

• Quasi-van der Waals Epitaxial Growth of γ'-GaSe Thin Films on GaAs(111)B Substrates
• Review of Nanolayered Post-transition Metal Monochalcogenides: Synthesis, Properties, and Applications
• Epitaxial growth of atomically thin Ga2Se2 films on c-plane sapphire substrates
• Multi-modal machine learning analysis of GaSe molecular beam epitaxy growth conditions
• Unveiling the growth mode diagram of GaSe on sapphire