Researchers from the University of California, Berkeley, led by Professor Yubo Yuan, have conducted a comprehensive theoretical study on the carrier mobility in Bi$_2$O$_2$Se, an emerging high-performance layered semiconductor. The team, including Ziye Zhu, Jiaming Hu, and Wenbin Li, published their findings in the journal “Physical Review Materials.”
The study focuses on understanding the transport properties of electrons and holes in Bi$_2$O$_2$Se, which is known for its excellent stability and potential applications in the energy sector. Using first-principles calculations, the researchers solved the Boltzmann transport equation to determine the mobilities of both electrons and holes, considering electron-phonon scattering and ionized impurity scattering.
The findings reveal that Bi$_2$O$_2$Se exhibits high electron mobilities in both the in-plane and out-of-plane directions, while hole mobilities are significant only in the in-plane direction. This unique behavior indicates a three-dimensional (3D) electron transport and two-dimensional (2D) hole transport mechanism. At room temperature (300 K), the intrinsic electron mobility is calculated to be 447 cm²/V·s, and the hole mobility is 29 cm²/V·s in the in-plane direction. These values are primarily influenced by Fröhlich electron-phonon interactions.
One of the notable findings is the exceptionally high low-temperature electron mobility in Bi$_2$O$_2$Se, exceeding 1.0×10⁵ cm²/V·s. Additionally, the electron mobility above 50 K is robust against ionized impurity scattering over a wide range of impurity concentrations, making it a promising material for various applications. By incorporating the Hall effect into their analysis, the researchers predicted an in-plane electron Hall mobility of 517 cm²/V·s at 300 K, which aligns well with experimental data.
The practical applications of these findings for the energy sector are significant. The high electron mobility and stability of Bi$_2$O$_2$Se make it a potential candidate for advanced electronic and optoelectronic devices, such as transistors, photovoltaic cells, and sensors. The unique transport properties could also be leveraged in the development of next-generation energy storage solutions and other energy-related technologies.
This research provides valuable insights into the carrier transport mechanisms in Bi$_2$O$_2$Se and offers predictive benchmarks for future theoretical and experimental investigations. The detailed understanding of its electronic properties will aid in the design and optimization of devices utilizing this promising semiconductor material.
This article is based on research available at arXiv.