Band structure and optical properties of hexagonal In-rich In(x)Al(1-x)N alloys

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Materials Science

Background:

• Indium Aluminum Nitride (In(x)Al(1-x)N) alloys are crucial for optoelectronic devices.
• Understanding their electronic and optical properties is key to material design.
• In-rich compositions require detailed investigation.

Purpose of the Study:

• To investigate the electronic and optical properties of In-rich In(x)Al(1-x)N alloys.
• To employ advanced computational methods for accurate property prediction.
• To analyze the impact of composition on the bandgap and optical response.

Main Methods:

• Full potential linear augmented plane wave (FP-LAPW) calculations.
• Density Functional Theory (DFT) with Engel-Vosko's generalized gradient approximation.
• Supercell models for varying compositions (x = 0.9375, 0.8125, 0.6875).

Main Results:

• Calculated band structures and densities of states.
• Determined the imaginary part of the dielectric function, ε(2)(ω).
• Observed good agreement between calculated and experimental bandgap dependencies on composition.
• Identified a valence band ordering reversal between x = 0.8125 and x = 0.6875.
• Related high-energy absorption features to critical points and determined van Hove singularity energies.

Conclusions:

• The study provides a comprehensive understanding of electronic and optical properties for In-rich In(x)Al(1-x)N alloys.
• The findings support experimental observations and offer insights into band structure modifications.
• The identified valence band reversal and optical absorption features are significant for device applications.