The spontaneous polarization of In-doped κ-Ga₂O₃ by first-principles calculation

The crystal structure, band structure, density of states, and optical properties of κ-(Ga1−xInx)2O3 (x = 0, 0.125, 0.25, 0.5) were studied using the first-principles calculation based on the density functional theory. With the increase of In content x, the bandgap of κ-(Ga1−xInx)2O3 decreases, while the light absorption coefficient increases. The spontaneous polarization of κ-(Ga1−xInx)2O3 was calculated qualitatively using the Born effective charge. The results suggested that κ-(Ga1−xInx)2O3 is also a material with spontaneous polarization properties. The spontaneous polarization in the extended c-axis has increased 1.27 times, from 27.31 to 34.58 μC/cm2, with the increase of In content from 0 to 0.5. This work paves the way for modulating spontaneous polarization of wide bandgap semiconductors. It provides a theoretical basis for the potential application of κ-(Ga1−xInx)2O3 in high electron mobility transistors, quantum well-infrared photodetectors, and photovoltaic materials.