Structural characterisation of high-mobility Cd₃As₂ films crystallised on SrTiO₃

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Chemistry

Background:

• Cadmium arsenide (Cd₃As₂) is recognized for its high electron mobility.
• The discovery of a topological semimetal state in Cd₃As₂ necessitates high-quality epitaxial films.
• Controlled growth of Cd₃As₂ films is crucial for exploring its advanced electronic properties.

Purpose of the Study:

• To report the structural characterization of Cd₃As₂ films grown on strontium titanate (SrTiO₃) substrates.
• To investigate the high-temperature solid-phase epitaxy process for Cd₃As₂ film fabrication.
• To understand the crystallisation mechanisms governing film growth.

Main Methods:

• Solid-phase epitaxy of Cd₃As₂ on (001) SrTiO₃ substrates at temperatures up to 600°C.
• Utilisation of optimized capping layers and substrates for controlled growth.
• Systematic characterisation of films annealed at various temperatures, including rocking-curve width measurements.

Main Results:

• Epitaxial growth of (112)-oriented Cd₃As₂ films with high crystallinity (rocking-curve width of 0.02°).
• Achieved high electron mobility exceeding 30,000 cm²/Vs.
• Identified a two-step crystallisation process (out-of-plane followed by in-plane) dependent on annealing temperature.

Conclusions:

• High-temperature solid-phase epitaxy provides a viable route for fabricating high-quality Cd₃As₂ films.
• The growth process enables the study of topological semimetal states and quantum transport phenomena.
• The findings facilitate advanced material design for next-generation electronic devices.