Structure Prediction And Properties Of Semiconductor Materials Based On High Throughput Screening

With the continuous advancement of science and technology,the design and synthesis of new materials have become the key to achieving more applications.Researchers can use first-principles calculations and other methods to calculate and predict materials to quickly obtain information about their physical properties.This allows researchers to more efficiently screen and design semiconductor materials with specific properties,thus accelerating the development and application of new semiconductor materials.In addition,material computing methods can help researchers understand the physical nature of materials,provide guidance for the optimal design of materials,and further promote the research and application of semiconductor materials.In the past few decades,materials scientists have discovered and prepared many new semiconductor materials with excellent properties through continuous exploration and experimentation.These materials not only have better electrical and optical properties but also have higher stability and lower cost.Therefore,in order to continuously break through the theoretical limits of traditional materials,an increasing number of researchers are beginning to use materials calculation methods to design and predict new semiconductor materials,with the aim of playing a more important role in future applications.Based on high-throughput screening technology and first-principles calculations,this paper proposes three new alumina structures,three new gallium oxide structures,and one new silicon semiconductor structure.The properties of the proposed materials were predicted using the CASTEP and VASP programs based on density functional theory（DFT）.The following are brief introductions to several of the works.By using graph and group theory-based random strategy（RG²）code,27 new silicon semiconductor structures were selected from 99 silicon structures,including 8 with direct bandgaps and 19 with indirect bandgaps.Due to the superior performance of direct bandgap silicon compared to indirect bandgap silicon in optoelectronic devices,especially in solar cells,one of the direct bandgap silicon,Fmmm Si₇₂,was selected for systematic study.The electronic band structure shows that Fmmm Si₇₂ is a direct bandgap semiconductor with a bandgap of 1.41 e V.In addition,it also has good absorption ability in the visible light wavelength region,making it very suitable for solar cells and with potential applications in the field of photovoltaics.Using high-throughput screening and DFT,23 new Al₂O₃ structures were screened out from 84 Al₂O₃ structures,among which three structures P2₁/c,Pnma-I,and Pnma-II Al₂O₃ with good stability were obtained.These three Al₂O₃ structures have dynamical stability,mechanical stability,and good thermal stability,and can remain thermally stable at high temperatures of up to 2000 K.With increasing pressure,P2₁/c Al₂O₃ transforms to Ca Ir O₃-type Al₂O₃ at 75-80 GPa.The electronic band structures indicate that all three new structures are ultrawide bandgap semiconducting materials with bandgaps ranging from 5.74 to 6.40 e V,and P2₁/c Al₂O₃ has a direct bandgap,and Pnma-I and Pnma-II Al₂O₃ hava indirect bandgaps.Both P2₁/c and Pnma-I Al₂O₃ have B/G ratios greater than1.75,indicating their ductility.These new materials have potential applications in optoelectronic materials,microelectronic materials,and thermal barrier coating materials.Based on high-throughput screening and density functional theory,three Ga₂O₃structures,m P20 Ga₂O₃,o P20-I Ga₂O₃,and o P20-II Ga₂O₃,were predicted from 45structures.All of the structures are dynamically and mechanically stable and maintain thermal stability at high temperatures up to 1000 K.m P20 Ga₂O₃ is a quasi-direct wide-bandgap semiconductor with a bandgap of 3.83 e V,while o P20-I Ga₂O₃ and o P20-II Ga₂O₃ are direct wide-bandgap semiconductors with bandgaps of 3.60 e V and 3.70 e V,respectively.In addition,the results indicate that these structures have low electron effective masses,which are advantageous for them to be potential candidate materials for high-power electronic devices.