β-Ga_(2)O_(3)/4H-SiC异质结界面的结构和电子性质

Structural and electronic properties of theβ-Ga_(2)O_(3)/4H-SiC heterojunction interface

利用第一性原理计算,系统性地研究了β-Ga_(2)O_(3)/4H-SiC异质结界面的结构和电子性质。利用满足电子计数规则的成键模型,构建了具有粗糙度小和带隙干净的绝缘界面,Si-O键在该界面的化学键中占主导地位。计算结果表明:对于β-Ga_(2)O_(3)和4H-SiC而言,利用杂化泛函计算得到的带隙分别为4.7 eV和3.35 eV,与实验值吻合较好;对于β-Ga_(2)O_(3)/4H-SiC异质结界面,该界面表现出半导体特性,其直接带隙为0.46 eV;同时,β-Ga_(2)O_(3)与4H-SiC形成Ⅱ型能带对齐,计算得到的价带偏移为1.72 eV,导带偏移为0.18 eV。所得结果对设计基于β-Ga_(2)O_(3)和4HSiC的电子器件具有重要意义。

By using first-principles calculation,the structural and electronic properties of theβ‒Ga_(2)O_(3)/4H‒SiC heterojunction interface are systematically investigated.An insulating interface with small roughness and clean bandgap is constructed by using a bonding model that satisfies the electron counting rules.Si‒O bonding dominates the chemical bonding at this interface.The computational results show that forβ‒Ga_(2)O_(3)and 4H‒SiC,the bandgaps obtained by using hybrid functional calculations are 4.7 eV and 3.35 eV,which are in good agreement with the experimental values.For theβ‒Ga_(2)O_(3)/4H‒SiC heterojunction interface,the interface exhibits semiconducting properties with a direct band gap of 0.46 eV.Meanwhile,theβ‒Ga_(2)O_(3)and 4H‒SiC form a type-Ⅱenergy band alignment,and the calculated valence band offset is 1.72 eV and a conduction band offset is 0.18 eV.The obtained results are of great significance for the design of electronic devices based onβ‒Ga_(2)O_(3)and 4H‒SiC.