Growth-Pathway-Controlled van der Waals Epitaxy of Phase-Selective Tin Sulfides

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Controlling crystalline phase and interfacial strain in van der Waals (vdW) epitaxy of polymorphic 2D materials is a significant challenge.
• Tin sulfides are a promising platform for studying these effects, but deterministic phase control and growth-pathway impacts are not well understood.

Purpose of the Study:

• To investigate growth-pathway-controlled vdW epitaxy for phase-selective tin sulfides on WSe2.
• To explore the effects of growth conditions on phase stability and strain accommodation in tin sulfide heterostructures.

Main Methods:

• Utilized a two-zone chemical vapor deposition (CVD) system for controlled growth.
• Investigated tin sulfide epitaxy on WSe2 under varying sulfur conditions (rich vs. deficient).
• Employed sequential growth strategies to manage strain and phase evolution.

Main Results:

• Sulfur-rich conditions yielded hexagonal SnS2 with in-plane epitaxial alignment to WSe2.
• Sulfur-deficient conditions led to orthorhombic SnS with multiple epitaxial registries and substrate-mediated strain.
• Sequential growth using a SnS2 buffer layer successfully produced strain-free orthorhombic SnS.

Conclusions:

• Growth-pathway control enables deterministic phase selection in vdW epitaxy.
• Decoupling epitaxial alignment from strain accommodation is achievable through controlled growth strategies.
• This approach enhances structural integrity in lattice-mismatched vdW heterostructures.