Engineering the band gap, fermi level, electronic and magnetic properties of transparent conducting oxides

Abstract

Transparent conducting oxides (TCOs) play important roles in both solar industries and laboratory researches. In this thesis, we have studied two TCO candidates, which are Ta doped anatase TiO2 and SrNbO3. All the thin films were prepared by pulsed laser deposition (PLD). Some basic and well known properties of TiO2 have been introduced and newly discovered properties in this thesis work, such as the shift of energy band levels with Ta concentration, metal to insulator transition and transition of transport mechanisms at low temperatures for TiO2 thin film upon Ta doping have been described in detail. In addition, we have studied Ni impurity mediated reversible ferromagnetism in rutile TiO2 substrate upon annealing. Besides TiO2, we have studied another TCOs material SrNbO3+d which has optical bandgap close to 4 eV and also has potential application as photocatalyst in water splitting.