Structural and electronic properties of dilute-selenide gallium oxide

Abstract

First-principles density functional theory is applied to investigate the electronic and structural properties of dilute-Se β-Ga2(O1-xSex)3 alloys with the Se-content ranging from 0% to 16.67%. The findings showed that the addition of Se has significant effect on the β-Ga2O3 alloy properties. The equilibrium volume and lattice parameters of β-Ga2(O1-xSex)3 alloys are presented, showing a general expansion with increasing Se-content. Further analysis indicates the expansion rate in the c (001) direction is much larger than that in the a and b directions, in which the information provides important guidance for the manufacturing of the β-Ga2(O1-xSex)3/Ga2O3-based material. From our analysis of the band structures, the β-Ga2(O1-xSex)3 alloys exhibit indirect bandgap property with the bandgap energy decreasing dramatically from 4.868 eV to 2.759 eV. The wavelength derived from the direct bandgap energy covers a regime from 255 nm to 475 nm, implying the potential of β-Ga2(O1-xSex)3 alloys in an ultraviolet photodetector and visible light applications. In addition, electron effective masses are calculated and presented for the β-Ga2(O1-xSex)3 alloys, in which the electron effective mass reduces as the Se-content increases. As a part of a highly mismatched alloy semiconductor class, dilute-Se Ga2(O1-xSex)3 is discussed for the first time with no prior literature in our work, and our findings indicate the potential implementation of GaOSe alloys for electronic and optoelectronic device applications.