Selective Synthesis of Large-Area Monolayer Tin Sulfide from Simple Substances

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Tin monosulfide (SnS) and tin disulfide (SnS2) are stable layered materials with potential for spin-valleytronics and photodetectors.
• Monolayer SnS exhibits unique properties like ferroelectricity and persistent spin helix due to its low symmetry.
• Synthesizing large-area, atomic-thickness SnS is difficult because of strong interlayer interactions from lone pair electrons.

Purpose of the Study:

• To develop a method for growing large-area, atomic-thickness tin monosulfide (SnS) crystals.
• To overcome the challenges associated with SnS synthesis, particularly the enhanced interlayer interactions.

Main Methods:

• Chemical vapor deposition (CVD) using high-purity elemental precursors.
• Controlled variation of sulfur vapor concentration relative to tin.
• Controlled sublimation of bulk SnS crystals to obtain monolayer crystals.

Main Results:

• Selective growth of p-type SnS achieved by adjusting precursor ratios.
• Successful synthesis of monolayer SnS crystals with lateral scales up to several tens of micrometers.
• Demonstrated a viable method for producing high-quality tin sulfide at the atomic scale.

Conclusions:

• The developed CVD and sublimation techniques enable the production of large-scale, monolayer SnS crystals.
• These findings facilitate the exploration of tin sulfide-based materials for advanced electronic and photonic device applications.
• Overcoming synthesis challenges opens new avenues for utilizing SnS in spin-valleytronics and photodetectors.