Pure Hexagonal Diamond with Symmetry-Doping Properties.

Area of Science:

• Materials Science
• Solid State Physics
• Computational Materials Science

Background:

• Wide band gap materials are crucial for electronic devices, but asymmetrical doping, particularly n-type diamond, remains a significant challenge.
• Current limitations in doping hinder the full application potential of diamond in advanced electronics.

Purpose of the Study:

• To investigate the doping behavior of various elements in six diamond polytypes.
• To identify a diamond polytype with favorable electronic properties and doping characteristics for improved device performance.
• To address the challenge of asymmetrical doping in wide band gap materials.

Main Methods:

• Computational investigation of six diamond polytypes.
• Doping simulations with various elements to analyze band structures and carrier effective masses.
• Calculation of impurity formation energies, donor/acceptor levels, and ionization energies.

Main Results:

• Pure hexagonal (2H) diamond exhibits a band gap of 4.42 eV and the smallest carrier effective masses among the studied polytypes.
• 2H-diamond shows significantly higher electron (4250 cm²·V^-1·s^-1) and hole (5840 cm²·V^-1·s^-1) mobilities compared to 3C-diamond.
• Phosphorus and boron exhibit lower ionization energies in 2H-diamond (0.14 eV and 0.19 eV, respectively) compared to 3C-diamond (0.32 eV and 0.58 eV), facilitating easier excitation at room temperature.
• Reduced impurity formation energy in 2H-diamond attributed to its C_3v symmetry.

Conclusions:

• 2H-diamond is a promising theoretical candidate to replace 3C-diamond as a wide band gap material due to its superior electronic properties and doping characteristics.
• The findings provide a pathway for realizing high-quality n-type diamond and advancing diamond-based electronic devices.
• This research offers a potential solution for asymmetrical doping challenges in other wide band gap materials.