CC BY 4.0 UnportedMulazzi, M.Reichmann, F.Becker, A.Klesse, W.M.Alippi, P.Fiorentini, V.Parisini, A.Bosi, M.Fornari, R.2021-10-202021-10-202019https://oa.tib.eu/renate/handle/123456789/7071https://doi.org/10.34657/6118The electronic structure of ε-Ga2O3 thin films has been investigated by ab initio calculations and photoemission spectroscopy with UV, soft, and hard X-rays to probe the surface and bulk properties. The latter measurements reveal a peculiar satellite structure in the Ga 2p core level spectrum, absent at the surface, and a core-level broadening that can be attributed to photoelectron recoil. The photoemission experiments indicate that the energy separation between the valence band and the Fermi level is about 4.4 eV, a valence band maximum at the Γ point and an effective mass of the highest lying bands of – 4.2 free electron masses. The value of the bandgap compares well with that obtained by optical experiments and with that obtained by calculations performed using a hybrid density-functional, which also reproduce well the dispersion and density of states.enghttps://creativecommons.org/licenses/by/4.0/620600Binary alloysCalculationsElectronic structureElectronsGallium compoundsPhotoelectron spectroscopyUranium alloysValence bandsVanadium alloysX raysAb initio calculationsCore-level spectraEnergy separationsFree electron massHybrid density functionalOptical experimentsSatellite structureValence-band maximumsCore levelsArticle