Exploring the structural, electronic, and transport properties in thickness-dependent two-dimensional Ga₂O₃induced by...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Semiconductor Physics

Background:

• Two-dimensional (2D) Gallium Oxide (Ga₂O₃) is a promising wide-bandgap semiconductor.
• Native point defects, specifically oxygen vacancies (V_O) and gallium vacancies (V_Ga), critically influence semiconductor properties.
• Understanding these defects is essential for tailoring Ga₂O₃ for electronic devices.

Purpose of the Study:

• To systematically investigate the impact of native V_O and V_Ga on the structural stability, electronic structure, carrier mobility, and conductivity of thickness-dependent 2D Ga₂O₃.
• To elucidate the distinct effects of V_O and V_Ga on the bandgap engineering and transport properties.
• To provide insights into defect engineering strategies for next-generation Ga₂O₃-based devices.

Main Methods:

• First-principles calculations were employed to study the electronic and structural properties of 2D Ga₂O₃ with varying thicknesses (monolayer, bilayer, trilayer).
• Analysis of native V_O and V_Ga configurations to determine their effects on mid-gap states, bandgaps, and carrier types (donor/acceptor).
• Simulation of carrier mobility (electron and hole) and conductivity trends as a function of film thickness and vacancy type.

Main Results:

• Oxygen vacancies (V_O) in 2D Ga₂O₃ introduce deep donor states, reducing the bandgap and significantly enhancing electron mobility, reaching ~12,154.89 cm²V^-1s^-1 in bilayer structures.
• Gallium vacancies (V_Ga) introduce shallow acceptor states, enabling potential p-type doping, with bandgaps ranging from 2.31 eV (monolayer) to 1.84 eV (trilayer) and decreasing hole mobilities.
• Both V_O and V_Ga induce thickness-dependent changes in conductivity, mirroring the trends observed in carrier mobilities, and exhibit distinct dimensional band features and anisotropic transport properties.

Conclusions:

• Native V_O and V_Ga act as crucial defect centers that can be engineered to tune the electronic and transport properties of 2D Ga₂O₃.
• The study highlights the potential for achieving high electron mobility via V_O and p-type conductivity via V_Ga in 2D Ga₂O₃.
• These findings offer valuable guidance for defect engineering strategies to optimize 2D Ga₂O₃ for advanced electronic and optoelectronic applications.