Cover Feature: High Electron Mobility in Heteroepitaxial β‐Ga ₂ O ₃ and Enhanced Electrical Conductivity in (In 0.5 Ga 0.5 ) ₂ O ₃ by Modifying Donor Energy Levels (Phys. Status Solidi RRL 3/2026)

The cover illustrates the effect of indium incorporation in Si-doped β-Ga2O3 on donor energy levels and carrier (electron) concentration. The top-right band diagram represents Si-doped β-Ga2O3, where donor states lie relatively deeper below the conduction band, resulting in a lower free-electron population. The bottom-right band diagram illustrates Si-doped (InXGa1-X)2O3, where indium incorporation modifies the local atomic environment, shifting donor states closer to the conduction band and leading to enhanced carrier activation and a higher electron concentration. The top-left and bottom-left lattice structures illustrate Si-doped β-Ga2O3 and Si-doped (InXGa1-X)2O3, respectively. The band-diagram schematics emphasize the redistribution of donor energy levels and the resulting increase in conduction-band electron density, highlighting the origin of improved electrical conductivity in indium-incorporated Ga2O3. More details can be found in the Research Article (DOI: 10.1002/pssr.202500391) by Farida A. Selim and co-workers.