Semiconductor Performance Optimization on Quasi-Two-Dimensional Bi₂O₂(SSe_1-) through Monotonous Alloying

Area of Science:

• Materials Science
• Solid-State Physics
• Nanotechnology

Background:

• Bismuth oxychalcogenides (Bi₂O₂X) are promising quasi-2D materials with high electron mobility, air stability, and excellent photoelectric properties.
• Precise control over their properties is essential for advancing practical applications in electronics and optoelectronics.

Purpose of the Study:

• To synthesize epitaxial Bi₂O₂(S,Se) films through controlled alloying of sulfur and selenium.
• To investigate the impact of elemental composition on the structural, electronic, and electrical properties of these films.
• To optimize heterostructures for enhanced device performance.

Main Methods:

• Epitaxial film synthesis using monotonous alloying of sulfur (S) and selenium (Se).
• Characterization of lattice constants, band gaps, and electrical properties as a function of composition.
• Fabrication and measurement of heterostructures incorporating a Bi₂SeO₅ (BSO) oxide layer.

Main Results:

• Lattice constants, band gaps, and electrical properties were found to vary systematically with the S/Se elemental composition.
• An enhanced field-effect mobility of approximately 215 cm²/(V s) was achieved.
• An excellent on/off ratio of around 10⁶ was observed in Bi₂O₂(S_0.4Se_0.6) heterostructures with a BSO layer.

Conclusions:

• Monotonous alloying of S and Se provides a viable route for tuning the properties of Bi₂O₂X materials.
• The demonstrated high performance in optimized heterostructures highlights the potential of these materials for next-generation electronic devices.
• This work paves the way for novel designs and applications of 2D bismuth oxychalcogenides.