Theoretical And Experimental Investigation Of The Electronic Properties Of The Wide Band-Gap Transparent Semiconductor Mgga2o4

We present an experimental and theoretical study of the electronic structure of the transparent conductive oxide semiconductor MgGa2O4. Its valence band and the core levels have been measured experimentally by angle-resolved photoemission spectroscopy and compared to theoretical ab initio density-functional calculations. The bands stem from oxygen orbitals and have a dispersion of about 0.6 eV and high effective masses, in agreement with the calculations. Angle-resolved measurements of the Ga 3d core levels indicate a sizable upward band bending, which in combination with an exact model potential yielded a quantitative estimate of the spatial extension of the depletion region, the effective Debye length in the material, and the extrinsic bulk carrier density.