Structural and electronic properties of dilute-selenide gallium oxide

First-principles density functional theory is applied to investigate the electronic and structural properties of dilute-Se beta-Ga-2(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 beta-Ga2O3 alloy properties. The equilibrium volume and lattice parameters of beta-Ga-2(O(1-x)Sex)(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 beta-Ga-2(O1-xSex)(3)/Ga2O3-based material. From our analysis of the band structures, the beta-Ga-2(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 beta-Ga-2(O1-xSex)(3) alloys in an ultraviolet photodetector and visible light applications. In addition, electron effective masses are calculated and presented for the beta-Ga-2(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 Ga-2(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. (C) 2019 Author(s).