Tailoring of defect levels by deformations: Te-antisite in CdTe

Area of Science:

• Solid State Physics
• Materials Science
• Computational Materials Science

Background:

• The Te-antisite defect in Cadmium Telluride (CdTe) is a critical factor influencing its electronic properties.
• Understanding defect behavior is crucial for optimizing CdTe for detector applications.

Purpose of the Study:

• To investigate the properties of the Te-antisite defect in neutral Cadmium Telluride (CdTe) using ab initio calculations.
• To analyze the impact of various deformations (1D, 2D, 3D) on defect energy levels and formation energies.
• To explore the role of Jahn-Teller distortions on defect states and their correlation with experimental observations.

Main Methods:

• Ab initio calculations were employed to model the Te-antisite defect in CdTe.
• The study analyzed the effects of 1D, 2D, and 3D deformations on defect properties.
• Jahn-Teller distortions and their influence on defect level positions were investigated.

Main Results:

• Two-dimensional (2D) deformation was found to be most effective in shifting defect levels towards band edges, potentially widening the bandgap.
• The Jahn-Teller distorted configuration positions the 2A1(a) defect level near the valence band.
• This calculated defect level position aligns with experimentally observed 'unknown deep donor' states.

Conclusions:

• Two-dimensional deformation offers a promising route to improve Cadmium Telluride (CdTe) detector performance by manipulating defect states.
• The findings provide insights into the electronic structure and defect bonding within CdTe.
• The study correlates theoretical defect level positions with experimental data, aiding in the understanding of CdTe material properties.