Epitaxial Stabilization of Tetragonal Cesium Tin Iodide

Area of Science:

• Materials Science
• Solid-State Physics
• Optoelectronics

Background:

• Hybrid organic-inorganic halide perovskites are used in optoelectronic devices like photovoltaics, LEDs, and lasers.
• Tin-based halide perovskites (e.g., CsSnX₃) offer lead-free alternatives, but achieving high-quality crystalline films with minimal defects is challenging.

Purpose of the Study:

• To demonstrate the single-domain epitaxial growth of cesium tin iodide (CsSnI₃) on potassium chloride (KCl) substrates.
• To investigate the phase behavior and electronic properties of epitaxially grown CsSnI₃.
• To explore the potential for growing advanced structures like quantum wells and photodetectors.

Main Methods:

• Epitaxial growth of CsSnI₃ on single-crystal KCl substrates.
• In situ real-time diffraction techniques to monitor growth and phase.
• Fabrication of multilayer quantum wells and lateral photodetector architectures.

Main Results:

• Successful single-domain epitaxial growth of CsSnI₃ on KCl.
• Discovery of a new epitaxially-stabilized tetragonal phase of CsSnI₃ at room temperature.
• Demonstration of multilayer 2D quantum wells and epitaxial films in a lateral photodetector.

Conclusions:

• Epitaxial growth provides a route to control phase and electronic properties of halide perovskites.
• This work expands the range of accessible epitaxially grown materials in the perovskite family.
• The findings pave the way for advanced lead-free perovskite-based optoelectronic devices.