Manipulation of the electronic structure of β-Ga₂O₃by adsorbates

β-Ga₂O₃ is one of the most promising candidates for power electronic devices owing to its wide bandgap, high breakdown voltage, and excellent thermal stability compared to the widely used semiconductor, silicon. In order for this material to be used in practical devices, one of the key issues is to understand its electronic structure and to find an efficient way to manipulate it. Here we introduce the electronic structure of heavily electron-doped β-Ga₂O₃ investigated using angle-resolved photoemission spectroscopy. The observed electronic structure is in good agreement with energy-loss spectra and calculated results. Moreover, the electronic structure undergoes a transition upon introducing foreign atoms. Our findings suggest a viable route towards the manipulation of electronic structure of β-Ga₂O₃ via adsorbates.