Universal tellurization-mediated buffer layer strategy derived from substrate-induced decomposition for large-area...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) materials offer unique electronic and optoelectronic properties for advanced devices.
• Bulk lead telluride (PbTe) shows topological properties, but its bulk nature obscures these characteristics.
• Fabricating high-quality 2D PbTe is challenging due to material decomposition.

Purpose of the Study:

• To develop a reliable method for synthesizing large-area lead telluride (PbTe) monolayers.
• To investigate the structural and electronic properties of PbTe monolayers on different substrates.
• To explore the potential of 2D PbTe for next-generation electronic and optoelectronic applications.

Main Methods:

• A tellurization-mediated buffer layer strategy was employed for PbTe monolayer fabrication.
• Sequential steps included molecular decomposition, tellurization, and epitaxial growth on Ag(111), Cu(111), and Au(111) substrates.
• Scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) were used for characterization.

Main Results:

• High-quality PbTe monolayers with tetragonal lattices were successfully grown on Ag(111), Cu(111), and Au(111) via buffer layers.
• PbTe monolayers exhibited an apparent height of 2 Å and a lattice constant of 0.8 nm.
• Moiré superstructures were observed on AgTe and CuTe buffer layers, indicating substrate-dependent growth.
• The PbTe monolayer on AgTe showed a significantly enhanced bandgap of 2.3 eV compared to bulk PbTe.

Conclusions:

• The tellurization-mediated buffer layer strategy enables controlled synthesis of large-area PbTe monolayers.
• PbTe monolayers possess tunable electronic properties, with a notably larger bandgap than bulk PbTe.
• This work lays the foundation for utilizing 2D PbTe in atomic-scale electronic and optoelectronic devices.