A hybrid functional method for screening the p-type defects in wide gap semiconductor α-LiAlTe₂

Area of Science:

• Materials Science
• Solid State Physics
• Optoelectronics

Background:

• Transparent conducting materials (TCMs) are crucial for transparent electronics.
• Ternary telluride α-LiAlTe₂ shows potential as a TCM due to its wide band gap and high transmittance.
• Research on the electrical conductivity of α-LiAlTe₂ is limited.

Purpose of the Study:

• To investigate the electrical conductivity of α-LiAlTe₂.
• To screen for potential impurity phases and evaluate intrinsic and extrinsic defects.
• To determine the feasibility of achieving p-type conductivity in α-LiAlTe₂.

Main Methods:

• Utilized the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional method for defect screening.
• Demarcated stable phase regions of α-LiAlTe₂ under thermodynamic equilibrium.
• Evaluated intrinsic defects (Li_int, Al_int) and p-type extrinsic defects (Mg_Al, Ca_Al, N_Te, P_Te, As_Te).

Main Results:

• Intrinsic defects Li_int and Al_int induce n-type conductivity.
• Mg_Al and N_Te act as shallow acceptor defects with transition energy levels at 0.24 eV and 0.21 eV above the VBM, respectively.
• Under specific conditions, N_Te has a low formation energy (0.35 eV), and p-type conductivity exceeding 60,800 S m⁻¹ is achievable at a hole density of 10²⁰ cm⁻³.

Conclusions:

• α-LiAlTe₂ exhibits tunable conductivity through defect engineering.
• The N_Te defect is a viable pathway for achieving high p-type conductivity.
• α-LiAlTe₂ is a strong candidate for optoelectronic applications due to its electrical and optical properties.