Point defects in ZnO: an approach from first principles.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Zinc oxide (ZnO) exhibits complex native point defect behavior crucial for its electronic properties.
• Understanding these defects is vital for optimizing ZnO in electronic and optoelectronic applications.

Approach:

• A comprehensive review of first-principles studies on native point defects in ZnO.
• Evaluation of defect properties using various Density Functional Theory (DFT) approximations (LDA, GGA, LDA+U, GGA+U, hybrid functionals, sX, GW).
• Analysis of the impact of theoretical approximations and simulation models on defect property predictions.

Key Points:

• Oxygen vacancies are linked to non-stoichiometry and O-poor conditions but are deep donors.
• Zinc interstitials and anti-sites are shallow donors, but less likely in equilibrium n-type ZnO.
• Native defects, particularly oxygen vacancies, zinc interstitials, and anti-sites, contribute to hole compensation in p-type ZnO.
• n-type conductivity is attributed to impurities (like H), metastable oxygen vacancy states, and defect complexes.

Conclusions:

• Defect energetics favor native donor-type defects over acceptor-type defects in ZnO.
• Controlling oxygen partial pressure during growth is critical for suppressing hole compensation and achieving desired doping.
• First-principles calculations provide essential insights into defect structures and their influence on ZnO properties.