Ab initio determination of electron affinity of polar nitride surfaces, clean and under Cs coverage

摘要: Ab initio simulations were used to determine electron affinity, work function, and ionization energy of AlN, GaN, InN polar surfaces. The function depends weakly on the doping in bulk for nitrides due pinning Fermi level at all At metal surface, it is smaller, equal 3.87, 4.06, 2.99 eV InN, respectively, while nitrogen side, much higher: 9.14, 9.02, 8.24 eV. It was shown that affinity potential do not obey bandgap rule because quantum overlap repulsion surface band states: conduction metal, valence side. shift substantial, even more than 1 eV, which may explain first measured identified 1.9 eV later lower value 0.7 eV. Cesium both GaN surfaces does create bonding states, nevertheless initially decreases by charge transfer states reducing electric dipole layer so t...